Identifying a slice name information error in a dispersed storage network

ABSTRACT

A method begins by a processing module sending list digest requests to a set of dispersed storage (DS) units. The method continues with the processing module receiving list digest responses from at least some of the set of DS units and determining whether an inconsistency exists between first and second list digest responses of the list digest responses. The method continues with the processing module requesting at least a portion of each of the slice name information lists from first and second DS units of the set of DS units and identifying a slice name information error associated with the inconsistency based on the at least a portion of each of the slices name information lists of the first and second DS units when the inconsistency exists between first and second list digest responses of the list digest responses.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility patent application claims priority pursuant to35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 61/357,430,entitled “DISPERSAL METHOD IN A DISPERSED STORAGE SYSTEM,” (AttorneyDocket No. CS027), filed Jun. 22, 2010, pending, which is herebyincorporated herein by reference in its entirety and made part of thepresent U.S. Utility patent application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to computing systems and moreparticularly to data storage solutions within such computing systems.

2. Description of Related Art

Computers are known to communicate, process, and store data. Suchcomputers range from wireless smart phones to data centers that supportmillions of web searches, stock trades, or on-line purchases every day.In general, a computing system generates data and/or manipulates datafrom one form into another. For instance, an image sensor of thecomputing system generates raw picture data and, using an imagecompression program (e.g., JPEG, MPEG, etc.), the computing systemmanipulates the raw picture data into a standardized compressed image.

With continued advances in processing speed and communication speed,computers are capable of processing real time multimedia data forapplications ranging from simple voice communications to streaming highdefinition video. As such, general-purpose information appliances arereplacing purpose-built communications devices (e.g., a telephone). Forexample, smart phones can support telephony communications but they arealso capable of text messaging and accessing the internet to performfunctions including email, web browsing, remote applications access, andmedia communications (e.g., telephony voice, image transfer, musicfiles, video files, real time video streaming. etc.).

Each type of computer is constructed and operates in accordance with oneor more communication, processing, and storage standards. As a result ofstandardization and with advances in technology, more and moreinformation content is being converted into digital formats. Forexample, more digital cameras are now being sold than film cameras, thusproducing more digital pictures. As another example, web-basedprogramming is becoming an alternative to over the air televisionbroadcasts and/or cable broadcasts. As further examples, papers, books,video entertainment, home video, etc. are now being stored digitally,which increases the demand on the storage function of computers.

A typical computer storage system includes one or more memory devicesaligned with the needs of the various operational aspects of thecomputer's processing and communication functions. Generally, theimmediacy of access dictates what type of memory device is used. Forexample, random access memory (RAM) memory can be accessed in any randomorder with a constant response time, thus it is typically used for cachememory and main memory. By contrast, memory device technologies thatrequire physical movement such as magnetic disks, tapes, and opticaldiscs, have a variable response time as the physical movement can takelonger than the data transfer, thus they are typically used forsecondary memory (e.g., hard drive, backup memory, etc.).

A computer's storage system will be compliant with one or more computerstorage standards that include, but are not limited to, network filesystem (NFS), flash file system (FFS), disk file system (DFS), smallcomputer system interface (SCSI), internet small computer systeminterface (iSCSI), file transfer protocol (FTP), and web-baseddistributed authoring and versioning (WebDAV). These standards specifythe data storage format (e.g., files, data objects, data blocks,directories, etc.) and interfacing between the computer's processingfunction and its storage system, which is a primary function of thecomputer's memory controller.

Despite the standardization of the computer and its storage system,memory devices fail; especially commercial grade memory devices thatutilize technologies incorporating physical movement (e.g., a discdrive). For example, it is fairly common for a disc drive to routinelysuffer from bit level corruption and to completely fail after threeyears of use. One solution is to a higher-grade disc drive, which addssignificant cost to a computer.

Another solution is to utilize multiple levels of redundant disc drivesto replicate the data into two or more copies. One such redundant driveapproach is called redundant array of independent discs (RAID). In aRAID device, a RAID controller adds parity data to the original databefore storing it across the array. The parity data is calculated fromthe original data such that the failure of a disc will not result in theloss of the original data. For example, RAID 5 uses three discs toprotect data from the failure of a single disc. The parity data, andassociated redundancy overhead data, reduces the storage capacity ofthree independent discs by one third (e.g., n−1=capacity). RAID 6 canrecover from a loss of two discs and requires a minimum of four discswith a storage capacity of n−2.

While RAID addresses the memory device failure issue, it is not withoutits own failures issues that affect its effectiveness, efficiency andsecurity. For instance, as more discs are added to the array, theprobability of a disc failure increases, which increases the demand formaintenance. For example, when a disc fails, it needs to be manuallyreplaced before another disc fails and the data stored in the RAIDdevice is lost. To reduce the risk of data loss, data on a RAID deviceis typically copied on to one or more other RAID devices. While thisaddresses the loss of data issue, it raises a security issue sincemultiple copies of data are available, which increases the chances ofunauthorized access. Further, as the amount of data being stored grows,the overhead of RAID devices becomes a non-trivial efficiency issue.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a computingsystem in accordance with the invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing corein accordance with the invention;

FIG. 3 is a schematic block diagram of an embodiment of a distributedstorage processing unit in accordance with the invention;

FIG. 4 is a schematic block diagram of an embodiment of a grid module inaccordance with the invention;

FIG. 5 is a diagram of an example embodiment of error coded data slicecreation in accordance with the invention;

FIG. 6 is a flowchart illustrating an example of verifying a transactionin accordance with the invention;

FIG. 7 is a diagram illustrating an example of slice name mapping todispersed storage resources in accordance with the invention;

FIG. 8A is a flowchart illustrating an example of storing data andmetadata in accordance with the invention;

FIG. 8B is a flowchart illustrating an example of retrieving data andmetadata in accordance with the invention;

FIG. 9A is a diagram of an example of data mapping to slices inaccordance with the invention;

FIG. 9B is a diagram of another example of data mapping to slices inaccordance with the invention;

FIG. 10A is a diagram of another example of data mapping to slices inaccordance with the invention;

FIG. 10B is a diagram of another example of data mapping to slices inaccordance with the invention;

FIG. 10C is a flowchart illustrating an example of encoding data toproduce data slices and parity slices in accordance with the invention;

FIG. 11 is a flowchart illustrating an example of identifying a sliceerror in accordance with the invention;

FIG. 12 is a flowchart illustrating another example of identifying aslice error in accordance with the invention;

FIG. 13A is a diagram illustrating an example of a registry structure inaccordance with the invention;

FIG. 13B is a diagram illustrating an example of a registry entry inaccordance with the invention;

FIG. 13C is a flowchart illustrating an example of acquiring registryinformation in accordance with the invention;

FIG. 14 is a schematic block diagram of an embodiment of a registrydistribution system in accordance with invention;

FIG. 15A is a flowchart illustrating an example of updating a registryentry in accordance with the invention;

FIG. 15B is a flowchart illustrating an example of distributing registryinformation in accordance with the invention;

FIG. 16 is a flowchart illustrating an example of processing registryinformation in accordance with the invention;

FIG. 17A is a schematic block diagram of an embodiment of adeterministic all or nothing transform (AONT) encoder in accordance withinvention;

FIG. 17B is a flowchart illustrating an example of encoding data in toproduce a secure package in accordance with the invention;

FIG. 18A is a schematic block diagram of an embodiment of adeterministic all or nothing transform (AONT) decoder in accordance withthe invention;

FIG. 18B is a flowchart illustrating an example of decoding a securepackage to produce data in accordance with the invention;

FIG. 19 is a schematic block diagram of an embodiment of a hardwareauthentication system in accordance with the invention;

FIG. 20A is a flowchart illustrating an example of acquiring a signedcertificate in accordance with the invention;

FIG. 20B is a flowchart illustrating an example of verifying acertificate signing request (CSR) in accordance with the invention;

FIG. 21 is a schematic block diagram of an embodiment of a softwareupdate authentication system in accordance with the invention;

FIG. 22A is a flowchart illustrating an example of generating a signedsoftware update in accordance with the invention;

FIG. 22B is a flowchart illustrating an example of authenticating asigned software update in accordance with the invention;

FIG. 23 is a schematic block diagram of an embodiment of a cooperativestorage system in accordance with the invention;

FIG. 24A is a flowchart illustrating an example of storing data inaccordance with the invention;

FIG. 24B is a flowchart illustrating an example of retrieving data inaccordance with the invention;

FIG. 25 is a schematic block diagram of an embodiment of a mediaredistribution system in accordance with invention; and

FIG. 26 is a flowchart illustrating an example of redistributing mediain accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of a computing system 10 thatincludes one or more of a first type of user devices 12, one or more ofa second type of user devices 14, at least one distributed storage (DS)processing unit 16, at least one DS managing unit 18, at least onestorage integrity processing unit 20, and a distributed storage network(DSN) memory 22 coupled via a network 24. The network 24 may include oneor more wireless and/or wire lined communication systems; one or moreprivate intranet systems and/or public internet systems; and/or one ormore local area networks (LAN) and/or wide area networks (WAN).

The DSN memory 22 includes a plurality of distributed storage (DS) units36 for storing data of the system. Each of the DS units 36 includes aprocessing module and memory and may be located at a geographicallydifferent site than the other DS units (e.g., one in Chicago, one inMilwaukee, etc.). The processing module may be a single processingdevice or a plurality of processing devices. Such a processing devicemay be a microprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module may have an associatedmemory and/or memory element, which may be a single memory device, aplurality of memory devices, and/or embedded circuitry of the processingmodule. Such a memory device may be a read-only memory, random accessmemory, volatile memory, non-volatile memory, static memory, dynamicmemory, flash memory, cache memory, and/or any device that storesdigital information. Note that if the processing module includes morethan one processing device, the processing devices may be centrallylocated (e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that when the processing module implements one or more ofits functions via a state machine, analog circuitry, digital circuitry,and/or logic circuitry, the memory and/or memory element storing thecorresponding operational instructions may be embedded within, orexternal to, the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry. Still further notethat, the memory element stores, and the processing module executes,hard coded and/or operational instructions corresponding to at leastsome of the steps and/or functions illustrated in FIGS. 1-26.

Each of the user devices 12-14, the DS processing unit 16, the DSmanaging unit 18, and the storage integrity processing unit 20 may be aportable computing device (e.g., a social networking device, a gamingdevice, a cell phone, a smart phone, a personal digital assistant, adigital music player, a digital video player, a laptop computer, ahandheld computer, a video game controller, and/or any other portabledevice that includes a computing core) and/or a fixed computing device(e.g., a personal computer, a computer server, a cable set-top box, asatellite receiver, a television set, a printer, a fax machine, homeentertainment equipment, a video game console, and/or any type of homeor office computing equipment). Such a portable or fixed computingdevice includes a computing core 26 and one or more interfaces 30, 32,and/or 33. An embodiment of the computing core 26 will be described withreference to FIG. 2.

With respect to the interfaces, each of the interfaces 30, 32, and 33includes software and/or hardware to support one or more communicationlinks via the network 24 and/or directly. For example, interfaces 30support a communication link (wired, wireless, direct, via a LAN, viathe network 24, etc.) between the first type of user device 14 and theDS processing unit 16. As another example, DSN interface 32 supports aplurality of communication links via the network 24 between the DSNmemory 22 and the DS processing unit 16, the first type of user device12, and/or the storage integrity processing unit 20. As yet anotherexample, interface 33 supports a communication link between the DSmanaging unit 18 and any one of the other devices and/or units 12, 14,16, 20, and/or 22 via the network 24.

In general and with respect to data storage, the system 10 supportsthree primary functions: distributed network data storage management,distributed data storage and retrieval, and data storage integrityverification. In accordance with these three primary functions, data canbe distributedly stored in a plurality of physically different locationsand subsequently retrieved in a reliable and secure manner regardless offailures of individual storage devices, failures of network equipment,the duration of storage, the amount of data being stored, attempts athacking the data, etc.

The DS managing unit 18 performs distributed network data storagemanagement functions, which include establishing distributed datastorage parameters, performing network operations, performing networkadministration, and/or performing network maintenance. The DS managingunit 18 establishes the distributed data storage parameters (e.g.,allocation of virtual DSN memory space, distributed storage parameters,security parameters, billing information, user profile information,etc.) for one or more of the user devices 12-14 (e.g., established forindividual devices, established for a user group of devices, establishedfor public access by the user devices, etc.). For example, the DSmanaging unit 18 coordinates the creation of a vault (e.g., a virtualmemory block) within the DSN memory 22 for a user device (for a group ofdevices, or for public access). The DS managing unit 18 also determinesthe distributed data storage parameters for the vault. In particular,the DS managing unit 18 determines a number of slices (e.g., the numberthat a data segment of a data file and/or data block is partitioned intofor distributed storage) and a read threshold value (e.g., the minimumnumber of slices required to reconstruct the data segment).

As another example, the DS managing module 18 creates and stores,locally or within the DSN memory 22, user profile information. The userprofile information includes one or more of authentication information,permissions, and/or the security parameters. The security parameters mayinclude one or more of encryption/decryption scheme, one or moreencryption keys, key generation scheme, and data encoding/decodingscheme.

As yet another example, the DS managing unit 18 creates billinginformation for a particular user, user group, vault access, publicvault access, etc. For instance, the DS managing unit 18 tracks thenumber of times user accesses a private vault and/or public vaults,which can be used to generate a per-access bill. In another instance,the DS managing unit 18 tracks the amount of data stored and/orretrieved by a user device and/or a user group, which can be used togenerate a per-data-amount bill.

The DS managing unit 18 also performs network operations, networkadministration, and/or network maintenance. As at least part ofperforming the network operations and/or administration, the DS managingunit 18 monitors performance of the devices and/or units of the system10 for potential failures, determines the devices and/or unit'sactivation status, determines the devices' and/or units' loading, andany other system level operation that affects the performance level ofthe system 10. For example, the DS managing unit 18 receives andaggregates network management alarms, alerts, errors, statusinformation, performance information, and messages from the devices12-14 and/or the units 16, 20, 22. For example, the DS managing unit 18receives a simple network management protocol (SNMP) message regardingthe status of the DS processing unit 16.

The DS managing unit 18 performs the network maintenance by identifyingequipment within the system 10 that needs replacing, upgrading,repairing, and/or expanding. For example, the DS managing unit 18determines that the DSN memory 22 needs more DS units 36 or that one ormore of the DS units 36 needs updating.

The second primary function (i.e., distributed data storage andretrieval) begins and ends with a user device 12-14. For instance, if asecond type of user device 14 has a data file 38 and/or data block 40 tostore in the DSN memory 22, it send the data file 38 and/or data block40 to the DS processing unit 16 via its interface 30. As will bedescribed in greater detail with reference to FIG. 2, the interface 30functions to mimic a conventional operating system (OS) file systeminterface (e.g., network file system (NFS), flash file system (FFS),disk file system (DFS), file transfer protocol (FTP), web-baseddistributed authoring and versioning (WebDAV), etc.) and/or a blockmemory interface (e.g., small computer system interface (SCSI), internetsmall computer system interface (iSCSI), etc.). In addition, theinterface 30 may attach a user identification code (ID) to the data file38 and/or data block 40.

The DS processing unit 16 receives the data file 38 and/or data block 40via its interface 30 and performs a distributed storage (DS) process 34thereon (e.g., an error coding dispersal storage function). The DSprocessing 34 begins by partitioning the data file 38 and/or data block40 into one or more data segments, which is represented as Y datasegments. For example, the DS processing 34 may partition the data file38 and/or data block 40 into a fixed byte size segment (e.g., 2¹ to2^(n) bytes, where n=>2) or a variable byte size (e.g., change byte sizefrom segment to segment, or from groups of segments to groups ofsegments, etc.).

For each of the Y data segments, the DS processing 34 error encodes(e.g., forward error correction (FEC), information dispersal algorithm,or error correction coding) and slices (or slices then error encodes)the data segment into a plurality of error coded (EC) data slices 42-48,which is represented as X slices per data segment. The number of slices(X) per segment, which corresponds to a number of pillars n, is set inaccordance with the distributed data storage parameters and the errorcoding scheme. For example, if a Reed-Solomon (or other FEC scheme) isused in an n/k system, then a data segment is divided into n slices,where k number of slices is needed to reconstruct the original data(i.e., k is the threshold). As a few specific examples, the n/k factormay be 5/3; 6/4; 8/6; 8/5; 16/10.

For each slice 42-48, the DS processing unit 16 creates a unique slicename and appends it to the corresponding slice 42-48. The slice nameincludes universal DSN memory addressing routing information (e.g.,virtual memory addresses in the DSN memory 22) and user-specificinformation (e.g., user ID, file name, data block identifier, etc.).

The DS processing unit 16 transmits the plurality of EC slices 42-48 toa plurality of DS units 36 of the DSN memory 22 via the DSN interface 32and the network 24. The DSN interface 32 formats each of the slices fortransmission via the network 24. For example, the DSN interface 32 mayutilize an internet protocol (e.g., TCP/IP, etc.) to packetize theslices 42-48 for transmission via the network 24.

The number of DS units 36 receiving the slices 42-48 is dependent on thedistributed data storage parameters established by the DS managing unit18. For example, the DS managing unit 18 may indicate that each slice isto be stored in a different DS unit 36. As another example, the DSmanaging unit 18 may indicate that like slice numbers of different datasegments are to be stored in the same DS unit 36. For example, the firstslice of each of the data segments is to be stored in a first DS unit36, the second slice of each of the data segments is to be stored in asecond DS unit 36, etc. In this manner, the data is encoded anddistributedly stored at physically diverse locations to improved datastorage integrity and security. Further examples of encoding the datasegments will be provided with reference to one or more of FIGS. 2-26.

Each DS unit 36 that receives a slice 42-48 for storage translates thevirtual DSN memory address of the slice into a local physical addressfor storage. Accordingly, each DS unit 36 maintains a virtual tophysical memory mapping to assist in the storage and retrieval of data.

The first type of user device 12 performs a similar function to storedata in the DSN memory 22 with the exception that it includes the DSprocessing. As such, the device 12 encodes and slices the data fileand/or data block it has to store. The device then transmits the slices11 to the DSN memory via its DSN interface 32 and the network 24.

For a second type of user device 14 to retrieve a data file or datablock from memory, it issues a read command via its interface 30 to theDS processing unit 16. The DS processing unit 16 performs the DSprocessing 34 to identify the DS units 36 storing the slices of the datafile and/or data block based on the read command. The DS processing unit16 may also communicate with the DS managing unit 18 to verify that theuser device 14 is authorized to access the requested data.

Assuming that the user device is authorized to access the requesteddata, the DS processing unit 16 issues slice read commands to at least athreshold number of the DS units 36 storing the requested data (e.g., toat least 10 DS units for a 16/10 error coding scheme). Each of the DSunits 36 receiving the slice read command, verifies the command,accesses its virtual to physical memory mapping, retrieves the requestedslice, or slices, and transmits it to the DS processing unit 16.

Once the DS processing unit 16 has received a read threshold number ofslices for a data segment, it performs an error decoding function andde-slicing to reconstruct the data segment. When Y number of datasegments has been reconstructed, the DS processing unit 16 provides thedata file 38 and/or data block 40 to the user device 14. Note that thefirst type of user device 12 performs a similar process to retrieve adata file and/or data block.

The storage integrity processing unit 20 performs the third primaryfunction of data storage integrity verification. In general, the storageintegrity processing unit 20 periodically retrieves slices 45, and/orslice names, of a data file or data block of a user device to verifythat one or more slices have not been corrupted or lost (e.g., the DSunit failed). The retrieval process mimics the read process previouslydescribed.

If the storage integrity processing unit 20 determines that one or moreslices is corrupted or lost, it rebuilds the corrupted or lost slice(s)in accordance with the error coding scheme. The storage integrityprocessing unit 20 stores the rebuild slice, or slices, in theappropriate DS unit(s) 36 in a manner that mimics the write processpreviously described.

FIG. 2 is a schematic block diagram of an embodiment of a computing core26 that includes a processing module 50, a memory controller 52, mainmemory 54, a video graphics processing unit 55, an input/output (IO)controller 56, a peripheral component interconnect (PCI) interface 58,at least one IO device interface module 62, a read only memory (ROM)basic input output system (BIOS) 64, and one or more memory interfacemodules. The memory interface module(s) includes one or more of auniversal serial bus (USB) interface module 66, a host bus adapter (HBA)interface module 68, a network interface module 70, a flash interfacemodule 72, a hard drive interface module 74, and a DSN interface module76. Note the DSN interface module 76 and/or the network interface module70 may function as the interface 30 of the user device 14 of FIG. 1.Further note that the IO device interface module 62 and/or the memoryinterface modules may be collectively or individually referred to as IOports.

The processing module 50 may be a single processing device or aplurality of processing devices. Such a processing device may be amicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on hard coding of the circuitry and/oroperational instructions. The processing module 50 may have anassociated memory and/or memory element, which may be a single memorydevice, a plurality of memory devices, and/or embedded circuitry of theprocessing module 50. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module 50includes more than one processing device, the processing devices may becentrally located (e.g., directly coupled together via a wired and/orwireless bus structure) or may be distributedly located (e.g., cloudcomputing via indirect coupling via a local area network and/or a widearea network). Further note that when the processing module 50implements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory and/ormemory element storing the corresponding operational instructions may beembedded within, or external to, the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.Still further note that, the memory element stores, and the processingmodule 50 executes, hard coded and/or operational instructionscorresponding to at least some of the steps and/or functions illustratedin FIGS. 1-26.

FIG. 3 is a schematic block diagram of an embodiment of a dispersedstorage (DS) processing module 34 of user device 12 and/or of the DSprocessing unit 16. The DS processing module 34 includes a gatewaymodule 78, an access module 80, a grid module 82, and a storage module84. The DS processing module 34 may also include an interface 30 and theDSnet interface 32 or the interfaces 68 and/or 70 may be part of user 12or of the DS processing unit 14. The DS processing module 34 may furtherinclude a bypass/feedback path between the storage module 84 to thegateway module 78. Note that the modules 78-84 of the DS processingmodule 34 may be in a single unit or distributed across multiple units.

In an example of storing data, the gateway module 78 receives anincoming data object that includes a user ID field 86, an object namefield 88, and the data field 40 and may also receive correspondinginformation that includes a process identifier (e.g., an internalprocess/application ID), metadata, a file system directory, a blocknumber, a transaction message, a user device identity (ID), a dataobject identifier, a source name, and/or user information. The gatewaymodule 78 authenticates the user associated with the data object byverifying the user ID 86 with the managing unit 18 and/or anotherauthenticating unit.

When the user is authenticated, the gateway module 78 obtains userinformation from the management unit 18, the user device, and/or theother authenticating unit. The user information includes a vaultidentifier, operational parameters, and user attributes (e.g., userdata, billing information, etc.). A vault identifier identifies a vault,which is a virtual memory space that maps to a set of DS storage units36. For example, vault 1 (i.e., user 1's DSN memory space) includeseight DS storage units (X=8 wide) and vault 2 (i.e., user 2's DSN memoryspace) includes sixteen DS storage units (X=16 wide). The operationalparameters may include an error coding algorithm, the width n (number ofpillars X or slices per segment for this vault), a read threshold T, awrite threshold, an encryption algorithm, a slicing parameter, acompression algorithm, an integrity check method, caching settings,parallelism settings, and/or other parameters that may be used to accessthe DSN memory layer.

The gateway module 78 uses the user information to assign a source name35 to the data. For instance, the gateway module 60 determines thesource name 35 of the data object 40 based on the vault identifier andthe data object. For example, the source name may contain a fileidentifier (ID), a vault generation number, a reserved field, and avault identifier (ID). As another example, the gateway module 78 maygenerate the file ID based on a hash function of the data object 40.Note that the gateway module 78 may also perform message conversion,protocol conversion, electrical conversion, optical conversion, accesscontrol, user identification, user information retrieval, trafficmonitoring, statistics generation, configuration, management, and/orsource name determination.

The access module 80 receives the data object 40 and creates a series ofdata segments 1 through Y 90-92 in accordance with a data storageprotocol (e.g., file storage system, a block storage system, and/or anaggregated block storage system). The number of segments Y may be chosenor randomly assigned based on a selected segment size and the size ofthe data object. For example, if the number of segments is chosen to bea fixed number, then the size of the segments varies as a function ofthe size of the data object. For instance, if the data object is animage file of 4,194,304 eight bit bytes (e.g., 33,554,432 bits) and thenumber of segments Y=131,072, then each segment is 256 bits or 32 bytes.As another example, if segment sized is fixed, then the number ofsegments Y varies based on the size of data object. For instance, if thedata object is an image file of 4,194,304 bytes and the fixed size ofeach segment is 4,096 bytes, the then number of segments Y=1,024. Notethat each segment is associated with the same source name.

The grid module 82 receives the data segments and may manipulate (e.g.,compression, encryption, cyclic redundancy check (CRC), etc.) each ofthe data segments before performing an error coding function of theerror coding dispersal storage function to produce a pre-manipulateddata segment. After manipulating a data segment, if applicable, the gridmodule 82 error encodes (e.g., Reed-Solomon, Convolution encoding,Trellis encoding, etc.) the data segment or manipulated data segmentinto X error coded data slices 42-44.

The value X, or the number of pillars (e.g., X=16), is chosen as aparameter of the error coding dispersal storage function. Otherparameters of the error coding dispersal function include a readthreshold T, a write threshold W, etc. The read threshold (e.g., T=10,when X=16) corresponds to the minimum number of error-free error codeddata slices required to reconstruct the data segment. In other words,the DS processing module 34 can compensate for X-T (e.g., 16−10=6)missing error coded data slices per data segment. The write threshold Wcorresponds to a minimum number of DS storage units that acknowledgeproper storage of their respective data slices before the DS processingmodule indicates proper storage of the encoded data segment. Note thatthe write threshold is greater than or equal to the read threshold for agiven number of pillars (X).

For each data slice of a data segment, the grid module 82 generates aunique slice name 37 and attaches it thereto. The slice name 37 includesa universal routing information field and a vault specific field and maybe 48 bytes (e.g., 24 bytes for each of the universal routinginformation field and the vault specific field). As illustrated, theuniversal routing information field includes a slice index, a vault ID,a vault generation, and a reserved field. The slice index is based onthe pillar number and the vault ID and, as such, is unique for eachpillar (e.g., slices of the same pillar for the same vault for anysegment will share the same slice index). The vault specific fieldincludes a data name, which includes a file ID and a segment number(e.g., a sequential numbering of data segments 1-Y of a simple dataobject or a data block number).

Prior to outputting the error coded data slices of a data segment, thegrid module may perform post-slice manipulation on the slices. Ifenabled, the manipulation includes slice level compression, encryption,CRC, addressing, tagging, and/or other manipulation to improve theeffectiveness of the computing system.

When the error coded data slices of a data segment are ready to beoutputted, the grid module 82 determines which of the DS storage units36 will store the EC data slices based on a dispersed storage memorymapping associated with the user's vault and/or DS storage unit 36attributes. The DS storage unit attributes may include availability,self-selection, performance history, link speed, link latency,ownership, available DSN memory, domain, cost, a prioritization scheme,a centralized selection message from another source, a lookup table,data ownership, and/or any other factor to optimize the operation of thecomputing system. Note that the number of DS storage units 36 is equalto or greater than the number of pillars (e.g., X) so that no more thanone error coded data slice of the same data segment is stored on thesame DS storage unit 36. Further note that EC data slices of the samepillar number but of different segments (e.g., EC data slice 1 of datasegment 1 and EC data slice 1 of data segment 2) may be stored on thesame or different DS storage units 36.

The storage module 84 performs an integrity check on the outboundencoded data slices and, when successful, identifies a plurality of DSstorage units based on information provided by the grid module. Thestorage module then outputs the encoded data slices 1 through X of eachsegment 1 through Y to the DS storage units. Each of the DS storageunits 36 stores its EC data slice(s) and maintains a local virtual DSNaddress to physical location table to convert the virtual DSN address ofthe EC data slice(s) into physical storage addresses.

In an example of a read operation, the user device 12 and/or 14 sends aread request to the DS processing unit 14, which authenticates therequest. When the request is authentic, the DS processing unit 14 sendsa read message to each of the DS storage units 36 storing slices of thedata object being read. The slices are received via the DSnet interface32 and processed by the storage module 84, which performs a parity checkand provides the slices to the grid module 82 when the parity check wassuccessful. The grid module 82 decodes the slices in accordance with theerror coding dispersal storage function to reconstruct the data segment.The access module 80 reconstructs the data object from the data segmentsand the gateway module 78 formats the data object for transmission tothe user device.

FIG. 4 is a schematic block diagram of an embodiment of a grid module 82that includes a control unit 73, a pre-slice manipulator 75, an encoder77, a slicer 79, a post-slice manipulator 81, a pre-slice de-manipulator83, a decoder 85, a de-slicer 87, and/or a post-slice de-manipulator 89.Note that the control unit 73 may be partially or completely external tothe grid module 82. For example, the control unit 73 may be part of thecomputing core at a remote location, part of a user device, part of theDS managing unit 18, or distributed amongst one or more DS storageunits.

In an example of write operation, the pre-slice manipulator 75 receivesa data segment 90-92 and a write instruction from an authorized userdevice. The pre-slice manipulator 75 determines if pre-manipulation ofthe data segment 90-92 is required and, if so, what type. The pre-slicemanipulator 75 may make the determination independently or based oninstructions from the control unit 73, where the determination is basedon a computing system-wide predetermination, a table lookup, vaultparameters associated with the user identification, the type of data,security requirements, available DSN memory, performance requirements,and/or other metadata.

Once a positive determination is made, the pre-slice manipulator 75manipulates the data segment 90-92 in accordance with the type ofmanipulation. For example, the type of manipulation may be compression(e.g., Lempel-Ziv-Welch, Huffman, Golomb, fractal, wavelet, etc.),signatures (e.g., Digital Signature Algorithm (DSA), Elliptic Curve DSA,Secure Hash Algorithm, etc.), watermarking, tagging, encryption (e.g.,Data Encryption Standard, Advanced Encryption Standard, etc.), addingmetadata (e.g., time/date stamping, user information, file type, etc.),cyclic redundancy check (e.g., CRC32), and/or other data manipulationsto produce the pre-manipulated data segment.

The encoder 77 encodes the pre-manipulated data segment 92 using aforward error correction (FEC) encoder (and/or other type of erasurecoding and/or error coding) to produce an encoded data segment 94. Theencoder 77 determines which forward error correction algorithm to usebased on a predetermination associated with the user's vault, a timebased algorithm, user direction, DS managing unit direction, controlunit direction, as a function of the data type, as a function of thedata segment 92 metadata, and/or any other factor to determine algorithmtype. The forward error correction algorithm may be Golay,Multidimensional parity, Reed-Solomon, Hamming, Bose Ray ChauduriHocquenghem (BCH), Cauchy-Reed-Solomon, or any other FEC encoder. Notethat the encoder 77 may use a different encoding algorithm for each datasegment 92, the same encoding algorithm for the data segments 92 of adata object, or a combination thereof.

The encoded data segment 94 is of greater size than the data segment 92by the overhead rate of the encoding algorithm by a factor of X/T, whereX is the width or number of slices, and T is the read threshold. In thisregard, the corresponding decoding process can accommodate at most X-Tmissing EC data slices and still recreate the data segment 92. Forexample, if X=16 and T=10, then the data segment 92 will be recoverableas long as 10 or more EC data slices per segment are not corrupted.

The slicer 79 transforms the encoded data segment 94 into EC data slicesin accordance with the slicing parameter from the vault for this userand/or data segment 92. For example, if the slicing parameter is X=16,then the slicer slices each encoded data segment 94 into 16 encodedslices.

The post-slice manipulator 81 performs, if enabled, post-manipulation onthe encoded slices to produce the EC data slices. If enabled, thepost-slice manipulator 81 determines the type of post-manipulation,which may be based on a computing system-wide predetermination,parameters in the vault for this user, a table lookup, the useridentification, the type of data, security requirements, available DSNmemory, performance requirements, control unit directed, and/or othermetadata. Note that the type of post-slice manipulation may includeslice level compression, signatures, encryption, CRC, addressing,watermarking, tagging, adding metadata, and/or other manipulation toimprove the effectiveness of the computing system.

In an example of a read operation, the post-slice de-manipulator 89receives at least a read threshold number of EC data slices and performsthe inverse function of the post-slice manipulator 81 to produce aplurality of encoded slices. The de-slicer 87 de-slices the encodedslices to produce an encoded data segment 94. The decoder 85 performsthe inverse function of the encoder 77 to recapture the data segment90-92. The pre-slice de-manipulator 83 performs the inverse function ofthe pre-slice manipulator 75 to recapture the data segment.

FIG. 5 is a diagram of an example of slicing an encoded data segment 94by the slicer 79. In this example, the encoded data segment includesthirty-two bits, but may include more or less bits. The slicer 79disperses the bits of the encoded data segment 94 across the EC dataslices in a pattern as shown. As such, each EC data slice does notinclude consecutive bits of the data segment 94 reducing the impact ofconsecutive bit failures on data recovery. For example, if EC data slice2 (which includes bits 1, 5, 9, 13, 17, 25, and 29) is unavailable(e.g., lost, inaccessible, or corrupted), the data segment can bereconstructed from the other EC data slices (e.g., 1, 3 and 4 for a readthreshold of 3 and a width of 4).

FIG. 6 is a flowchart illustrating an example of verifying atransaction. The method begins with step 102 where a processing module(e.g., of a dispersed storage (DS) processing unit, of a DS unit)determines an unverified transaction corresponding to a particulardispersed storage network (DSN) access request. Such a DSN accessrequest includes one or more of a transaction number, a read request, awrite request, a checked write request, a commit request, a rollbackrequest, and a check request. Such a transaction number may be utilizedto associate one or more messages and/or actions with a multistepsequence to accomplish a desired overall result of the DSN accessrequest. Such a transaction number may be generated to populate a firstDSN access request wherein the first DSN access request may be part of aplurality of messages and/or actions to facilitate the multistepsequence. Such a transaction number may be utilized to avoid conflictsincluding attempted simultaneous operations on a same revision of a sameslice. Generation of the transaction number includes forming thetransaction number based on elapsed seconds since Jan. 1, 1970 UTC withnanosecond, millisecond, and/or seconds of precision. For instance, thetransaction number is eight bytes in length.

An unverified transaction corresponds to an indeterminate status (e.g.,a desired condition or an undesired condition) associated with atransaction of the DSN access request. For example, a status of anundesired condition includes at least one DS units of a set of DS unitsthat did not receive a DSN access request and has no knowledge of atransaction number associated with the DSN access request. As anotherexample, a status of a desired condition includes each DS unit of theset of DS units did receive the DSN access request and has knowledge ofthe transaction number. In an instance, the unverified transactionbecomes a verified transaction when the indeterminate status transitionsto a determinate status by learning whether each DS unit of the set ofDS units has knowledge of the transaction number. Such a determinationof the unverified transaction may be based on one or more of atransaction table lookup, a query, a command, and a message.

The method continues at step 104 where the processing module determinesa set of DS units associated with the unverified transaction. Such adetermination may be based on one or more of a virtual DSN address tophysical location table query, a list, a DS unit identifier (ID), atransaction table, a vault lookup, a command, and a message.

The method continues at step 106 where the processing module sends atransaction verification request to the set of DS units, wherein thetransaction verification request includes the transaction number thatcorresponds to the particular DSN access request. Such a DSN accessrequest may be sent to the set of DS units concurrent with, or prior to,sending the transaction verification request to the set of DS units.

The method continues at step 108 where the processing module receivestransaction verification responses from at least some of the set of DSunits to produce received transaction verification responses. Such atransaction verification response may include one or more of atransaction number associated with the at least some of the set of DSunits, a transaction number list including transaction numbers activelyassociated with the at least some of the set of DS units, a hash digestof the transaction number list, and a transaction processing stateindicator corresponding to a state of processing each transaction thatis currently open (e.g., not fully processed). Alternatively, or inaddition to, processing module resends the transaction verificationrequest when a transaction verification response is not received withina time period after the transaction verification request was sent to aparticular DS unit of the set of DS units.

The method continues at step 110 where the processing module determineswhether a DS unit of the set of DS units does not provide a desiredtransaction verification response. Such a determination may be based onone or more of whether a transaction verification response was receivedfrom the DS unit within a time period, whether the transactionverification response includes the transaction number that correspondsto the particular DSN access request, whether the transactionverification response includes a hash digest that corresponds to theparticular DSN access request (e.g., substantially the same as a hashdigest from another DS unit), and whether the transaction verificationresponse does not include a transaction number included in a transactionverification response from another DS unit. For example, the processingmodule determines that the DS unit of the set of DS units does notprovide the desired transaction verification response when thetransaction verification response does not include the transactionnumber that corresponds to the particular DSN access request. The methodbranches to step 114 when processing module determines that the DS unitof the set of DS units does not provide the desired transactionverification response. In such a scenario, the processing moduledetermines that all of the transaction verification responses are notfavorable. The method continues to step 112 when the processing moduledetermines that the DS unit of the set of DS units does provide thedesired transaction verification response.

The method continues at step 112 where the processing module indicatesthat the DSN access request is verified when the desired transactionverification responses are favorable. Such verification of the DSNaccess request includes at least one of indicating that the DSN accessrequest is verified for the DS unit and indicating that the DSN accessrequest is verified for each DS unit of the set of DS units.

The method continues at step 114 where the processing module identifiesan undesired condition with processing the DSN access request when theDS unit of the set of DS units does not provide a desired transactionverification response. Such identifying of the undesired condition withprocessing the DSN access request includes detecting at least one of oneof the transaction verification responses does not include thetransaction number, the DS unit does not provide the one of thetransaction verification responses within a given time period, one ofthe transaction verification responses indicates that the DS unit didnot receive the DSN access request, and the one of the transactionverification responses includes the transaction number that is differentfrom a transaction number included in another one of the transactionverification responses.

The method continues at step 116 where the processing module initiates acorrective remedy for the undesired condition. Such initiating of thecorrective remedy for the undesired condition includes one or more ofinitiating a rebuild function for a data slice associated with the DSunit, wherein the data slice is identifiable based on the transactionnumber, resending the DSN access request to the set of DS units, sendingthe DSN access request to another set of DS units, and modifying the DSNaccess request to produce a modified DSN access request and sending themodified DSN access request to the set of DSN units or the another setof DSN units. Such initiating the rebuild function comprises at leastone of rebuilding the data slice to produce a rebuild data slice,sending a rebuilding request to a rebuilding entity, wherein the requestincludes a slice name of the data slice and wherein the rebuildingentity rebuilds the data slice, and sending the slice name to another DSunit for rebuilding the data slice. Alternatively, or in addition to,the method repeats back to step 102 to analyze another DSN accessrequest.

FIG. 7 is a diagram illustrating an example of slice name mapping todispersed storage resources. A slice name mapping includes a slice namelist 37 mapped to pillar storage 122. A slice name list 37 includes aplurality of slice name entries. Such a plurality of slice name entriesincludes one or more data slice name entries and one or more pairedmetadata slice name entries, wherein a number of metadata slice nameentries is substantially the same as a number of data slice nameentries. A plurality of slice name entries includes a dispersed storage(DS) routing information field 118 and a data identifier (ID) field 120.A DS routing information field 118 includes a plurality of DS routinginformation entries (e.g., pillar index, vault ID, generation ID). Sucha data ID field 120 includes a plurality of data ID entries (e.g.,data/metadata flag, object ID, data segment ID). In an implementationexample, the slice name entry is 48 bytes in length, the DS routinginformation entry is 24 bytes in length, and the data ID entry is 24bytes in length.

A pillar storage 122 includes sparse storage 124 and dense storage 126.Such a sparse storage 124 includes at least one DS unit 36. Such a densestorage 126 includes one or more DS units 36. Alternatively, the sparsestorage 124 and the dense storage 126 share a common DS unit 36. Densestorage 126 may be utilized to store encoded data slices of data such aslarge data objects and such sparse storage 124 may be utilized to storeencoded metadata slices, wherein metadata is associated with the data.Metadata may describe the data including one or more of a data objectname, a block number, a source name, slice name, a data type, a datalength, an author identifier, access permissions, a creation timestamp,a last modified timestamp, a format indicator, a file type indicator, animage associated with text of the data, text associated with an image ofthe data, a priority indicator, a security indicator, directoryinformation, and a performance indicator. The metadata may be small indata volume as compared to the data. For example, data may be tenmillion bytes and associated metadata may be one thousand bytes.Allocation of less memory (e.g., fewer DS units) to sparse storage ascompared to the allocation of DS units to dense storage may provide anefficiency improvement to the system.

A data ID field 120 may include a data/metadata flag. For example, amost significant bit of the data ID field 120 is utilized as thedata/metadata flag and distinguishes between slice names mapped to thedense storage 126 and slice names mapped to the sparse storage 124. Forexample, a slice name address containing a data/metadata flag equal tozero is mapped to slice names of metadata to be stored in the sparsestorage on 24. As another example, a slice name address containing adata/metadata flag equal to one is to slice names of data to be storedin the dense storage 126. A configuration pairs slice name addresses(e.g., a metadata slice name and a data slice name) that aresubstantially the same with the exception of the data/metadata flag ofthe data identifier field. As such, a slice name determinationefficiency may be provided when one part of a slice name pair is known(e.g. toggle the most significant bit of the data ID field 120 toproduce the slice name of the other). The method of utilization of themapping is discussed in greater detail with reference to FIGS. 8A-8B.

FIG. 8A is a flowchart illustrating an example of storing data andmetadata. The method begins with step 128 where a processing moduleobtains a data segment store. Such obtaining may be based on one or moreof receiving a data object to store, receiving a data segment to store,a command, and a message. For example, the processing module maydetermine to store one data segment of a data object. The methodcontinues at step 130 where the processing module determines metadataassociated with the data segment. The metadata includes at least one ofan object identifier (ID), object size, object type, object format,directory information, a file name, a file path, a source name, adispersed storage network (DSN) address, a snapshot ID, a segmentationallocation table (SAT) source name, object hash, access permissions, anda timestamp. Such a determination may be based on one or more of ananalysis of the data, information received with the data, informationappended to the data, an inspection of at least one portion of the data,a data object name, a data segment identifier, a table lookup, apredetermination, a command, and a message.

The method continues at step 132 where the processing module dispersedstorage error encodes the data segment to produce a set of encoded dataslices. The method continues at step 134 where the processing moduledispersed storage error encodes the metadata associated with the datasegment to produce a set of encoded metadata slices.

The method continues at step 136 where the processing module creates aset of data slice names for the set of encoded data slices. Suchcreation may be based on at least one of a data ID associated with thedata segment, a vault ID lookup, a directory lookup, a source name(e.g., including a vault ID, a generation ID, and a object number), avault source name (e.g., including a source name and a segment number),the set of encoded data slices, a hash of the data segment, and anobject number associated with the data ID.

The method continues at step 138 where the processing module creates aset of metadata slice names based on the set of data slice names. Suchcreation may be based on at least one of toggling a data/metadata flagof a data slice name of the set of data slice names to produce acorresponding metadata slice name of the set of metadata slice names,performing an exclusive OR (XOR) logical function on the data slice namewith a naming mask to produce the corresponding metadata slice name,adding a constant value to the data slice name to produce thecorresponding metadata slice name, and subtracting the constant valuefrom the data slice name to produce the corresponding metadata slicename.

The method continues at step 140 where the processing module sends theset of encoded data slices and the set of data slice names to adispersed storage network (DSN) memory, wherein the DSN memory stores anencoded data slice of the set of encoded data slices based on acorresponding one of the set of data slice names using a first level ofmemory allocation. For example, when two dispersed storage (DS) unitsare utilized, the processing module sends the encoded data slice and thecorresponding one of the set of data slice names to a first DS unit ofthe DSN memory, wherein memory space of the first DS unit is partitionedin accordance with the first level of memory allocation (e.g., allocatedto the storage of large encoded data slices). As another example, whenone DS unit is utilized, the processing module sends the encoded dataslice and the corresponding one of the set of data slice names to the DSunit of the DSN memory, wherein a first portion of memory space of theDS unit is partitioned in accordance with the first level of memoryallocation.

The method continues at step 142 where the processing module sends theset of encoded metadata slices and the set of metadata slice names tothe DSN memory, wherein the DSN memory stores an encoded metadata sliceof the set of encoded metadata slices based on a corresponding one ofthe set of metadata slice names using a second level of memoryallocation, and wherein the second level of memory allocation is smallerthan the first level of memory allocation. For example, when the two DSunits are utilized, the processing module sends the encoded metadataslice and the corresponding one of the set of metadata slice names to asecond DS unit of the DSN memory, wherein memory space of the second DSunit is partitioned in accordance with the second level of memoryallocation (e.g., allocated to the storage of smaller encoded metadataslices). As another example, when the one DS unit is utilized theprocessing module sends the encoded metadata slice and the correspondingone of the set of metadata slice names to the DS unit, wherein a secondportion of the memory space of the DS unit is partitioned in accordancewith the second level of memory allocation.

FIG. 8B is a flowchart illustrating an example of retrieving data andmetadata. The method begins with step 144 where a processing moduledetermines a set of data slice names corresponding to a data segmentpreviously stored in a dispersed storage network (DSN) memory as a setof encoded data slices. Such a determination may be based on one or moreof a lookup, a data identifier (ID), a data segment ID, apredetermination, and a message. The method continues at step 146 wherethe processing module determines a set of metadata slice names based onthe set of data slice names, wherein the metadata slice names correspondto metadata previously stored in the DSN memory as a set of encodedmetadata slices.

The method continues at step 148 where the processing module retrievesat least a decode threshold number of encoded data slices of the set ofencoded data slices from the DSN memory to produce received encoded dataslices utilizing the set of data slice names, wherein the DSN memoryretrieves an encoded data slice of the set of encoded data slices basedon a corresponding one of the set of data slice names using a firstlevel of memory allocation. The method continues at step 150 where theprocessing module retrieves at least a decode threshold number ofencoded metadata slices of the set of encoded metadata slices from theDSN memory to produce received encoded metadata slices utilizing the setof metadata slice names, wherein the DSN memory retrieves an encodedmetadata slice of the set of encoded metadata slices based on acorresponding one of the set of metadata slice names using a secondlevel of memory allocation, and wherein the second level of memoryallocation is smaller than the first level of memory allocation.

The method continues at step 152 where the processing module dispersedstorage error decodes the received encoded data slices to reproduce thedata segment. Alternatively, or in addition to, the processing modulemay dispersed storage error decode the received encoded data slices inaccordance with special dispersal parameters. For example, theprocessing module dispersed storage error decodes the received encodeddata slices based on special dispersal parameters from the metadata toreproduce the data segment. Alternatively, or in addition to, theprocessing module transforms the data segment utilizing a metadatafunction to produce transformed data in accordance with the metadata andsends the transformed data to a requesting entity. For example,processing module transforms the data utilizing a data decompressionalgorithm of the metadata to produce the transformed data. The methodcontinues at step 154 where the processing module dispersed storageerror decodes the received encoded metadata slices to reproduce themetadata.

FIG. 9A is a diagram of an example of data mapping to slices. Data 156is segmented to produce a plurality of data segments 158, wherein eachsuccessive data segment 158 includes successive portions of the data 156from the beginning to the end. Each data segment 158 is dispersedstorage error encoded to produce a plurality of slices 1-8. Such aplurality of slices 1-8 includes the data segment 158 as slices 1-5 andparity 160 as slices 6-8 when a pillar width n=8 and a decode thresholdk=5 and an encoding matrix of the dispersed storage error encodingincludes a unity matrix (e.g., generating slices 1-5 to be substantiallythe same as the data segment 158). Generation and structure of the datasegment 158 is discussed in greater detail with reference to FIG. 10A.

FIG. 9B is a diagram of another example of data mapping to slices. Data156 is segmented to produce a plurality of data segments 162, whereineach successive byte of data segment 162 includes every kth byte of thedata 156 from the beginning to the end (e.g., decode threshold=k). Eachdata segment 162 is dispersed storage error encoded to produce aplurality of slices 1-8. Such a plurality of slices 1-8 includes thedata segment 162 as slices 1-5 and parity 164 as slices 6-8 when apillar width n=8 and a decode threshold k=5 and an encoding matrix ofthe dispersed storage error encoding includes a unity matrix (e.g.,generating slices 1-5 to be substantially the same as the data segment162). Generation and structure of the data segment 162 is discussed ingreater detail with reference to FIG. 10B.

FIG. 10A is a diagram of another example of data mapping to slices. Themapping includes data 166 mapped into a final segment matrix 168. Thedata 166 includes any data file type, including text, such as a textstring “the quick brown dog jumps high.” A data segment is created byselecting each successive byte of the text string such that each sliceincludes successive characters of the data segment when the unity matrixis utilized in an error coding dispersal storage function. For example,slice one contains a first character set “the qu”, and slice 2 containsa second character set “ick br”, etc. A resulting file segment matrix168 includes a decode threshold number of rows. Each row of the finalsegment matrix 168 forms a slice.

FIG. 10B is a diagram of another example of data mapping to slices. Thedata mapping includes data 166 mapped to a transposition segment matrix170, which is mapped to a final segment matrix 172. A transpositionsegment matrix includes a number of columns substantially the same as adecode threshold (e.g., k) and a number of rows based on data segmentsize and the number of columns. The transposition segment make its 170is inverted the form the final segment matrix 172. As such, slices ofthe resulting final segment matrix 172 are formed based on selectingevery kth character of the original data string. A data segment isformed based on selecting the next successive string characters suchthat the data segment size is completed (e.g., rows multiplied bycolumns). Such characters of the text string are filled in from left toright in successive order. For example, a first row includes characters“the q”, a second row includes characters “uick”, a third row includescharacters “brown”, etc. as shown. Next, characters from thetransposition matrix are utilized to create the data slices. Asillustrated, a slice 1 row is formed from column 1 characters of thetransposition matrix. For example, slice 1 contains characters “tub j”.As another example, a slice 2 contains characters “hirduh”, a slice 3contains the characters “ecoomi”, a data slice 4 contains characters“kwgpg”, and a slice 5 contains the characters “q n sh”. Parity slices6-8 are formed from slices 1-5 in accordance with an error codingdispersal storage function. In an alternative embodiment, parity dataslices 6-8 are formed from the transposition matrix in accordance withthe error coding dispersal storage function. The method of operation togenerate data slices is discussed in greater detail with reference toFIG. 10C.

FIG. 10C is a flowchart illustrating an example of encoding data toproduce data slices and parity slices. A method begins at step 174 whereprocessing module creates a data segment from data. For example, theprocessing module may select a next successive set of bytes of the data,wherein a number of the set of bytes a data segment size. As illustratedin FIG. 10B, the data segment may be represented by the string “thequick brown dog jumps high”. Alternatively, the processing module maycreate the data segment by selecting every kth (e.g., decode threshold)byte of the data where each data segment is offset by one byte.

The method continues at step 176 where the processing module creates atransposition matrix based on the data segment. A number of columns ofthe transposition matrix equals the decode threshold k. The methodcontinues at step 178 where the processing module creates k data slicesbased on the transposition matrix. A number of rows of the slices equalsthe threshold k when a unity matrix is utilized as part of an associatederror coding dispersal storage function. The processing module forms thedata slice from the characters of the corresponding column of thetransposition matrix.

The method continues at step 180 where the processing module creates n-kparity slices based on the k slices in accordance with the error codingdispersal storage function. Alternatively, or in addition to, theprocessing module forms the parity slices from the transposition matrixin accordance with the error coding dispersal storage function.

A processing module may subsequently decode the slices encoded asdescribed above. In such a method, a processing module receives a decodethreshold k number of data slices, creates the transposition matrix byforming the columns of the transposition matrix from the received dataslices, and produces the data segment based on aggregating the rows ofthe transposition matrix back into the original data segment.

FIG. 11 is a flowchart illustrating an example of identifying a sliceerror. A slice error includes one or more of a missing slice, a slice ofthe wrong revision, and a slice that fails an integrity check. Themethod begins with step 182 where a processing module determines a rangeof slice names to test for slice errors. Such a determination may bebased on one or more of where a process left off last time, apredetermination, a list, an error message, and a command. The methodcontinues at step 184 where the processing module determines at leasttwo dispersed storage (DS) units to test such that the at least two DSunits are included in a common DS unit storage set utilized to storedata slices within the range of slice names to test. Such adetermination may be based on one or more of a lookup in a dispersedstorage network (DSN) address to physical location table, a DS unitstorage set list, a message, and a command.

The method continues at step 186 where the processing module sends theat least two DS units a list digest request message. A list digestrequest message includes at least one of a start slice name, an endslice name, and a maximum response count, wherein the start slice nameand the end slice name are based on the range of slice names to test(e.g., a portion of the range). A targeted DS unit receives the listdigest request message and calculates a hash of a slice name andrevision list, but excluding a pillar index field of the slice name,over the range of slice names between the start slice name and the endslice name. The targeted DS unit sends a list digest request responsemessage to the processing module. Such a list digest response messageincludes at least one of a digest, a digest length, a last slice name,and a slice count. The method continues at step 188 where the processingmodule receives two or more list digest response messages from the twoor more DS units to produce received list digest responses.

The method continues at step 190 where the processing module determineswhether the received list digest responses compare favorably to eachother. For example, the processing module determines that the comparisonis favorable when the digests are substantially the same from two ormore DS units. A test may provide a system improvement since it is arelatively quick way to determine whether the same slice revisions arestored in each of the DS units of the same DS unit storage set over theslice name range. The method repeats back to step 182 when theprocessing module determines that the list digest request responsemessages compare favorably (e.g., no slice errors). The method continuesto step 192 when the processing module determines that the received listdigest responses do not compare favorably.

The method continues at step 192 where the processing module determinesa sub-range of slice names to test. Such a determination may be based onone or more of the range of slice names to test, a predetermined size ofthe range, a priority indicator, a performance indicator, a list, anerror history record lookup, a command, and a message. The methodcontinues with step 194 where the processing module sends the at leasttwo DS units a list digest request message corresponding to thesub-range of slice names (e.g., a start slice name and an end slice namecorrespond to the sub-range). The method continues at step 188 where theprocessing module receives list digest response messages.

The method continues at 190 where the processing module determineswhether the list digest response messages compare favorably (e.g., forthe sub-range of slice names). The method loops back to step 192 to testanother sub-range within range of slice names tested when the processingmodule determines that the list digest response messages comparefavorably for the (current) sub-range of slice names. The loop repeatsuntil the processing module identifies at least one sub-range of slicenames where a slice error exists (e.g., that caused the initialcomparison of digests to fail). The processing module may test allpossible sub-ranges of slice names such that all slice names of theoriginal slice name range are tested to identify all possible sliceerrors. The method continues to step 200 when the processing moduledetermines that the list digest request response messages do not comparefavorably over the sub-range of slice names.

The method continues at step 200 where the processing module sends theat least two DS units a list range request message. Such a list rangerequest message may include a start slice name, an end slice name, and amaximum response count. A targeted DS unit receives the request,produces list range response message, and sends the list range responsemessage to the processing module. A list range response message mayinclude the following for each slice name: a slice revision count, aslice revision and slice length for each slice revision.

The method continues at step 202 where the processing module receiveslist range response messages from the DS units. The method continues atstep 204 where the processing module identifies a difference between thelist range request response messages by comparing the messages. Theidentification reveals DS units storing pillar slices of differentrevisions, different slices, or missing slices. Alternatively, or inaddition to, the processing module initiates a rebuilding process torebuild data slices in error.

FIG. 12 is a flowchart illustrating another example of identifying aslice error, which includes similar steps to FIG. 11. The method beginswith step 182 of FIG. 11 where processing module determines a range ofslice names test. The method continues at step 208 where the processingmodule determines a dispersed storage (DS) unit set to test. Such adetermination may be based on one or more of a lookup in a dispersedstorage network (DSN) address to physical location table, a DS unitstorage set list, a message, and a command.

The method continues at step 210 where the processing module sends listdigest requests to the set of DS units, wherein a list digest request ofthe list digest requests is requesting a representation of a slice nameinformation list regarding encoded data slices stored by a DS unit ofthe set of DS units. A slice name information list includes a pluralityof entries for a range of slice names, wherein an entry of the pluralityof entries includes a slice name of a corresponding one of the encodeddata slices, a slice revision count indicating a number of revisions ofthe slice name, and for a revision of the revisions of the slice names arevision number and a slice length indicator. A representation of theslice name information list includes at least one of a hash valueresulting from a hash function performed on entries of the slice nameinformation list, a compression value resulting from a compressionfunction performed on entries of the slice name information list, achecksum value resulting from a checksum function performed on theentries of the slice name information list, a hash-based messageauthentication code (HMAC) value resulting from an HMAC functionperformed on the entries of the slice name information list, and a maskgenerating function (MGF) value resulting from an MGF performed on theentries of the slice name information list. Such performing of the hashfunction on the entries of the slice name information list may exclude apillar index portion of a slice name (e.g., since the pillar indexportion will be different between slice names of different pillars forthe same data segment).

The method continues at step 212 where the processing module receiveslist digest responses from at least some of the set of DS units. A listdigest response includes one or more of hash value (e.g., a digest), adigest length, a last slice name (e.g., a last slice name associatedwith the hash value or a slice name in a subsequent test), and a slicecount (e.g., a number of slice names included in the hash value).

The method continues at step 214 where the processing module determineswhether an inconsistency exists between first and second list digestresponses of the list digest responses. Such determining whether theinconsistency exists between the first and the second list digestresponses includes at least one of a first hash value of the first listdigest response is not substantially equal to a second hash value of thesecond list digest response, a first checksum value of the first listdigest response is not substantially equal to a second checksum value ofthe second list digest response, a first HMAC value of the first listdigest response is not substantially equal to a second HMAC value of thesecond list digest response, and a first MGF value of the first listdigest response is not substantially equal to a second MGF value of thesecond list digest response.

The method loops back to step 182 of FIG. 11 to test another range ofslice names when the processing module determines that the inconsistencydoes not exist between the first and second list digest responses. Themethod continues to step 216 when the processing module determines thatthe inconsistency does exist between the first and second list digestresponses.

The method continues at step 216 where the processing module requests atleast a portion of each of the slice name information lists from firstand second DS units of the set of DS units, wherein the first DS unitprovided the first list digest response and the second DS unit providedthe second list digest response. The processing module receives the atleast the portion of each of the slice name information lists from thefirst and second DS units.

The method continues at step 218 with a processing module identifies aslice name information error associated with the inconsistency based onthe at least a portion of each of the slices name information lists ofthe first and second DS units. A slice name information error includesat least one of a missing encoded data slice error, a non-deletedencoded data slice error (e.g., an extra slice that should not exist),and a revision error (e.g., a revision count difference, a differentslice revision number, a different slice length). The identifying of theslice name information error includes establishing the at least aportion of the slice name information list from the first DS unit as acurrent slice name information list and identifying an entry of the atleast a portion of the slice name information list from the second DSunit that differs from a corresponding entry of the at least a portionof the slice name information list from the first DS unit to identifythe slice name information error. The establishing the at least aportion of the slice name information list from the first DS unit as thecurrent slice name information list includes determining that the atleast a portion of the slice name information list from the first DSunit substantially matches at least a portion of the slice nameinformation list from a third DS unit of the set of DS units.

The method continues at step 220 where the processing module adds theslice name information error to a rebuild list. Alternatively, or inAddition to, the Processing module facilitates initiation of arebuilding process to remedy the slice name information error.Alternatively, or in addition to, the method loops back to step 216 torequest slice name information lists for a different portion of theslice name information lists (e.g., when the slice name informationerror has not been identified). Alternatively, or in addition to, themethod loops back to step 182 of FIG. 11 to test another range of slicenames.

FIG. 13A is a diagram illustrating an example of a registry structure. Aregistry structure includes a registry 222, which includes a pluralityof entries 1-N. The entries include configuration and operationalinformation associated with a dispersed storage network (DSN). Theregistry information may be utilized by one or more DSN system elements,processing modules, computing devices, nodes, and units of the DSN. Forexample, a dispersed storage (DS) unit boots up and requires registryinformation to invoke an appropriate initial configuration and sustainedoperation. The registry information may change from time to time as afunction of one or more of software updates, security breaches,failures, new hardware, system architecture changes, power conditions,network failures, operational requirements, performance requirements,etc. The structure and contents of a typical registry entry isillustrated with reference to FIG. 13B. A method to acquire registryinformation is discussed with reference to FIG. 13C.

FIG. 13B is a diagram illustrating an example of a registry entry 224. Aregistry entry 224 includes one or more of an entry identifier (ID) 226,a timestamp 228, configuration data 230, a signer identifier (ID) 232,and an entry signature 234. The entry ID 226 includes a reference numberassociated with the registry entry and may be utilized to locate similarregistry entries. Each entry ID 226 is unique and never reused.Alternatively, the entry ID 226 is reused but can be distinguished fromother entry IDs other utilizing the timestamp 228 associated with theentry ID 226. The timestamp 228 may represent a system timestamp whenthe registry entry was created, received, verified, or processed by anelement of the DSN system. For example, a dispersed storage (DS)managing unit creates a timestamp 228 based on present time of a clockwhen a new registry entry is created. As another example, a DS unitoverwrites the timestamp 228 based on the present time of a clock whenthe registry entry 224 is received from the DS managing unit.

The configuration data 230 may be utilized by any element of a dispersedstorage network (DSN) to configure and operate in accordance with theregistry entry. The configuration data 230 may include one or more ofslice name range assignments, node internet protocol addresses,certificate authority addresses, authentication authorities addresses,vault identifiers, access control information, digital certificates,application software, driver software, verbal numbers, thresholdnumbers, etc.

The signer ID 232 represents an identity of a system element thatcreated and authenticated the registry entry 224 by way of populatingthe entry signature 234 with a valid signature. For example, the DSmanaging unit may populate the signer ID 232 with an identity of the DSmanaging unit when the DS managing unit creates the registry entry 224.

The entry signature 234 is populated with a signature to validate theregistry entry 224. For example, a processing module of the DS managingunit calculates a hash of registry element fields not including theentry signature 234 to produce a hash of the registry entry 224. Theprocessing module encrypts the hash of the registry entry 224 to producethe entry signature 234 utilizing a private key associated with aprivate/public key pair of the DS managing unit. The processing modulemay store the completed signed registry entry 224 in preparation fordistribution to elements of the DSN. The processing module of the DSmanaging unit may distribute the public key to elements of the DSN.Alternatively, or in addition to, the public key is included in theregistry entry 224 such that the public key is distributed as part ofthe registry entry 224. Elements of the DSN utilizes the public key todecrypt the entry signature 234 and compare it to a calculated hash ofthe registry entry 224 to validate the registry entry 224 as describedin greater detail with reference to FIG. 16.

FIG. 13C is a flowchart illustrating an example of acquiring registryinformation. The method begins with step 236 where a processing modulereboots to restart a processing module operation. The method continuesat step 238 where the processing module sends a registry informationrequest to a dispersed storage (DS) managing unit. Alternatively, theprocessing module sends the registry information request to any othermodule, element, node, unit of a dispersed storage network (DSN). Forexample, the processing module sends the registry information request toa processing module of a DS unit. As another example, the processingmodule sends the registry information request to a publisher.

The registry information request may include a processing moduleidentifier of the processing module and a request command for registryinformation. The registry information may include a portion of theregistry as described with reference to Figures 13A-13B. For example,the processing module requests a portion that includes most recentregistry entry changes. As another example, the processing modulerequests the entire registry. As yet another example, the processingmodule requests registry entries that include only certain types ofconfiguration data (e.g., those that relate only to a DS unit).

The method continues at step 240 where the processing module determineswhether a registry information response has been received. Such adetermination may be based on determining that the registry informationrequest response has not been received if the response has not beenreceived within an elapsed time period from the registry informationrequest. The method branches to step 244 when the processing moduledetermines that the registry information response has not been received.The method continues to step 242 when the processing module determinesthat the registry information response has been received. The methodcontinues at step 242 where the processing module updates a localregistry based on the registry information response. For example, theprocessing module saves received registry information as currentregistry information in the local registry (e.g., stored within the DSunit).

The method continues at step 244 where the processing module retrievesthe local registry. The local registry includes newer updates when theprocessing module received the registry information response and may notinclude newer updates, and may be outdated, when the processing moduledid not receive the registry information response. The method continuesat step 246 where the processing module compares an age of the localregistry to an age threshold based on a timestamp of the local registrycompared to the age threshold (e.g., where the age threshold is apredetermined or stored number). Alternatively, the age threshold isdynamic number as a function of a performance indicator and/or securityindicator.

The method repeats back to step 238 when the processing moduledetermines that the comparison of the age of the local registry to anage threshold is not favorable (e.g., the local registry is too old). Insuch a scenario, the processing module attempts to acquire more recentregistry information. The method continues to step 248 when theprocessing module determines that the comparison of the age of the localregistry to the age threshold is favorable (e.g., the local registry isnew enough). The method continues at step 248 where the processingmodule utilizes the local registry. In addition, the processing modulemay continue rebooting utilizing the local registry information to startand control applications and variable states as influenced byconfiguration data of one or more registry entries of the registryinformation.

FIG. 14 is a schematic block diagram of an embodiment of a registrydistribution system. Such a system includes a dispersed storage (DS)managing unit 18, a firewall 250, a plurality of publishers 252, and aplurality of system units (e.g., DS units 36, DS processing units 16,the storage integrity processing unit 20, user devices 12-14, DSmanaging units 18). Alternatively, the DS managing unit 18 is operablycoupled to the plurality of publishers 252 via a private network withoutthe use of the firewall 250. Such a firewall provides intrusionprotection such that registry information 254 is sent in a one-waydirection from the DS managing unit 18 to the publisher 252 minimizingany ability by an external entity to tamper with the registryinformation 254.

The DS managing unit 18 includes a registry 222 and sends registryinformation 254 from the registry 222 to the plurality of publishers 252from time to time. Each of the publishers 252 includes a processingmodule and memory and may be located at a geographically different sitethan the other system units. The publishers 252 are operably coupled tothe units of a dispersed storage network (DSN) via an internetconnection and/or a private network.

The publisher 252 receives the registry information 254 from the DSmanaging unit 18 from time to time. The publisher 252 sends the registryinformation 254 to one or more units of the DSN from time to time. Forexample, the publisher 252 pushes registry information 254 to a DS unitonce per day. As another example, the publisher 252 pushes the registryinformation 254 to a DS unit when there is a change in the registryinformation 254. As yet another example, the publisher 252 sends theregistry information 254 to a DS unit when the DS unit requests theregistry information 254. Methods to update and distribute registryinformation are described in greater detail with reference to FIGS. 15A,15B, and 16.

FIG. 15A is a flowchart illustrating an example of updating a registryentry. The method begins with step 256 where a processing moduledetermines whether a registry entry has changed. Such a determinationmay be based on one or more of a new input from a user of a dispersedstorage (DS) managing unit, a DS managing unit message, addition of anew software application, and addition of new system configurationparameters. The method repeats back to step 256 when the processingmodule determines that the registry entry has not changed. The methodcontinues to step 258 when the processing module determines that theregistry entry has changed.

The method continues at step 258 where the processing module determinesan entry identifier (ID). The entry ID includes one of a reuse of acurrent entry number with similar entry information and a newly assignedentry ID. Such a determination may be based on at least one of receptionof new information requiring a new entry ID and reception of informationto modify an existing entry ID. The method continues at step 260 wherethe processing module determines a timestamp based on a current systemclock. The method continues at step 262 where the processing moduledetermines configuration data. Such a determination is based on one ormore of information from a new input, a lookup, and analysis, a command,and a message.

The method continues at step 264 where the processing module determinesa signer ID based on one or more of an ID of a present unit, apredetermination, a command, and a message. The processing module formsa registry entry that includes the entry ID, the timestamp, theconfiguration data, and the signer ID. The method continues at step 266where the processing module calculates a hash of the registry entry toproduce a hash of the entry. For example the processing module utilizesa MD5 hash to produce the hash of the entry. The method continues atstep 268 where the processing module encrypts the hash of the entry toproduce an entry signature utilizing a private key of a private/publickey pair associated with a present unit (e.g., DS managing unit). Themethod continues at step 270 where the processing module saves theregistry entry and the entry signature in the registry for subsequentdistribution.

FIG. 15B is a flowchart illustrating an example of distributing registryinformation. The method begins with step 272 where a processing moduledetermines whether to send registry information. Such a determinationmay be based on one or more of a time period has elapsed since a lasttime that the registry information was sent, a change is detected in theregistry, and a registry information request message was received. Themethod loops at step 272 to determine whether to send registryinformation when the processing module determines not to send theregistry information. The method continues to step 274 when theprocessing module determines to send the registry information.

The method continues at step 274 where the processing module determininglatest entries of each entry identifier (ID). As such, the processingmodule determines a most recent registry entry when or more registryentries share a same entry ID based on comparing timestamps. The methodcontinues at step 276 where the processing module sends the latestregistry entries to a plurality of publishers and/or directly to systemunits. The method of operation of a system unit receiving the latestregistry entries is described with reference to FIG. 16.

FIG. 16 is a flowchart illustrating an example of processing registryinformation. The method begins with step 278 where a processing modulereceives a registry entry. The receiving includes the processing modulereceiving the registry entry as a push message and receiving theregistry entry in response to a request from the processing module. Theregistry entry may be one registry entry of a plurality of registryentries included in a portion of a registry.

The method continues at step 280 where the processing module determineswhether the received registry entry includes an entry identifier (ID)that is substantially different than a registry entry stored locally(e.g., previously received). The method branches to step 286 when theprocessing module determines that the registry entry ID is differentthan those stored locally. The method continues to step 282 when theprocessing module determines that the registry entry ID is the same asat least one registry entry stored locally. The method continues at step282 where the processing module determines whether a received registryentry timestamp is newer than a timestamp of all previous registryentries with a same entry ID. Such a determination is based on acomparison of a timestamp of the received registry entry to a timestampof each previously received registry entry, when the entry ID of thereceived registry entry is substantially the same as a entry ID of eachpreviously received registry entry.

The method branches to step 286 when the processing module determinesthat the received entry timestamp is newer than the previous timestamp.The method continues to step 284 when the processing module determinesthat the received entry timestamp is not newer than the previoustimestamp. The method continues at step 284 where the processing moduleignores (e.g., deletes without storing) the received registry entry whenthe processing module determines that received registry entry timestampis not newer than at least one previous registry entry of the same entryID.

The method continues at step 286 where the processing module calculatesa hash of the received registry entry to produce a hash of the entry.For example, the processing module utilizes a MD5 hash algorithm toproduce the hash of the entry. The method continues at step 288 wherethe processing module decrypts the entry signature of the registry entryto produce a decrypted entry signature utilizing a public key associatedwith a signer of the registry entry. For example, the processing moduleutilizes a public key associated with a DS managing unit ID when asigner ID is the same as a DS managing unit ID.

The method continues at step 290 where the processing module determineswhether the hash of the registry entry compares favorably to thedecrypted entry signature to determine if the registry entry is valid.The processing module determines that the comparison is favorable whenthe hash of the registry entry is substantially the same as thedecrypted entry signature. The method branches to step 294 when theprocessing module determines that the hash of the entry comparesfavorably to the decrypted entry signature (e.g., valid signature). Themethod continues to step 292 when the processing module determines thatthe hash of the entry does not compare favorably to the decrypted entrysignature. The method continues at step 292 where the processing moduleignores the received registry entry.

The method continues at step 294 where the processing module saves thereceived registry entry as a validated received registry entry. Forexample, the processing module stores the received registry entry in alocal memory. In addition, the processing module may update a timestampfield of the registry entry utilizing a current clock time and mayutilize configuration data included in the registry entry.

FIG. 17A is a schematic block diagram of an embodiment of adeterministic all or nothing transform (AONT) encoder. The deterministicAONT encoder includes a key generator 296, an encryptor 298, a hashingfunction 300, a masking function 302, and a combiner 304 to transformdata 306 (e.g., a data segment) into a secure package 316. The keygenerator 296 generates a deterministic key 308 from the data 306. Thegeneration of the deterministic key 308 includes performing a functionon the data 306 to produce the deterministic key 308, wherein thefunction includes one or more of a hashing function (e.g., messagedigest (MD)-5, secure hash algorithm (SHA)-1, SHA-256, SHA 512), achecksum function, a hash-based message authentication code (HMAC)(e.g., HMAC-MD-5), a mask generating function (MGF), and a compressionfunction. Such a MGF produces a deterministic pattern of bits of anydesired length based on an input. The encryptor 298 encrypts the data306 using the deterministic key 308 to produce encrypted data 310. Thehashing function 300 generates transformed data 312 from the encrypteddata 310. The generation of the transformed data includes performing afunction on the encrypted data 310 to produce the transformed data 312,wherein the function includes one or more of a hashing function, achecksum function (e.g., a cyclic redundancy check), a hash-basedmessage authentication code (HMAC), a mask generating function (MGF),and a compression function (e.g., repeated applications of a bitwiseexclusive OR).

The masking function 302 generates a masked key 314 from thedeterministic key 308 and the transformed data 312. The generation ofthe masked key 314 includes at least one of exclusive ORing (XOR) thedeterministic key 308 and the transformed data 312, adding thedeterministic key 308 and a modulo conversion of the transformed data312 (e.g., masked key=(deterministic key)+(transformed data) modulo C;where C=2̂(masked key length in bits)), and modifying the deterministickey 308 to produce a modified key and exclusive ORing the modified keyand the transformed data 312. The modifying of the deterministic key 308to produce the modified key includes at least one of adding apredetermined offset to the deterministic key 308, subtracting thepredetermined offset from the deterministic key 308, encrypting thedeterministic key 308 utilizing a secret key, exclusive ORing thedeterministic key 308 and the secret key, and appending the secret keyto the deterministic key 308. The combiner 304 combines the encrypteddata 310 and the masked key 314 to produce the secure package 316. Thecombining includes at least one of interleaving, appending, andencoding. For example, the masked key 314 is appended to the encrypteddata 310 to produce the secure package 316.

In an example of operation, the key generator 296 receives the data 306,wherein the data 306 is a data segment produced by an access module 80.The key generator 296 calculates the hash of the data 306 to produce thedeterministic key 308. The key generator 296 may truncate a hash valueto fit a desired key length of the deterministic key 308. Next, theencryptor 298 encrypts the data 306 utilizing the deterministic key 308to produce encrypted data 310. The hashing function 300 calculates aMD-5 hash of the encrypted data 310 to produce the transformed data 312.The masking function 302 exclusive ORs the deterministic key 308 withthe transformed data 312 to produce a masked key 314. The combiner 304appends the masked key 314 to the encrypted data 310 to produce a securepackage 316.

FIG. 17B is a flowchart illustrating an example of encoding data in toproduce a secure package. The method begins with step 318 where aprocessing module generates a deterministic key from data. The methodcontinues at step 320 where the processing module encrypts the datausing the deterministic key to produce encrypted data. The methodcontinues at step 322 where the processing module generates transformeddata from the encrypted data. The method continues at step 324 generatesa masked key from the deterministic key and the transformed data. Themethod continues at step 326 where the processing module combines themasked key and the encrypted data to produce a secure package. Themethod continues at step 328 where the processing module outputs thesecure package.

The outputting includes at least one of sending the secure package to awireless communication device for wireless communication of the securepacket, dispersed storage error encoding the secure package to produce aplurality of encoded data slices and outputting the plurality of encodeddata slices to a dispersed storage network (DSN) memory for storagetherein, and receiving a second secure package from a dispersed storagenetwork (DSN) memory and facilitating storage of the secure package inthe DSN memory when the secure package compares favorably to the secondsecure package. The receiving of the second secure package includes oneor more of retrieving a plurality of encoded second secure packageslices and dispersed storage error decoding the plurality of encodedsecond secure package slices to produce the second secure package.

Facilitating the storage of the secure package in the DSN memory whenthe secure package compares favorably to the second secure packageincludes comparing at least a portion of the secure package to at leasta corresponding portion of the second secure package and dispersedstorage error encoding the secure package to produce a plurality of setsof encoded data slices and sending the plurality of sets of encoded dataslices to the DSN memory for storage therein when the comparison issubstantially same. The comparing includes indicating that at least theportion of the second secure package compares favorably to at least theportion of the secure package when encrypted data of the second securepackage is substantially not the same as the encrypted data andindicating that at least the portion of the second secure packagecompares favorably to at least the portion of the secure package when amasked key of the second secure package is substantially not the same asthe masked key.

FIG. 18A is a schematic block diagram of an embodiment of adeterministic all or nothing transform (AONT) decoder. A deterministicAONT decoder includes a splitter 330, a hashing function 300, ade-masking function 332, and a decryptor 334 to transform a securepackage 316 into data 306. A splitter 330 extracts a masked key 314 andencrypted data 310 from the secure package 316. The splitting includesat least one of de-appending, de-interleaving, and decoding. Forexample, the splitter 330 de-appends the masked key 314 and encrypteddata 310 from the secure package 316. The hashing function 300 generatestransformed data 312 from the encrypted data 310. The de-maskingfunction 332 generates a deterministic key 308 from the masked key 314and the transformed data 312. The generating of the deterministic key308 includes at least one of exclusive ORing (XOR) the masked key 314and the transformed data 312, subtracting a modulo conversion of thetransformed data 312 from the masked key 314 (e.g., deterministickey=(masked key)−(transformed data) modulo C; where C=2̂(masked keylength in bits), and adding C if the result is <zero), and exclusiveORing the transformed data 312 and the masked key 314 to produce amodified key and modifying the modified key to produce the deterministickey 308. The modifying the modified key to produce the deterministic key308 includes at least one of adding a predetermined offset to themodified key, subtracting the predetermined offset from the modifiedkey, encrypting the modified key utilizing a secret key, exclusive ORingthe modified key and the secret key, and appending the secret key to themodified key. Such a decryptor 334 decrypts the encrypted data 310 basedon the deterministic key 308 to produce data 306.

In an example of operation, the splitter 330 receives a secure package(e.g., an encrypted data segment produced from retrieved encoded dataslices by a grid module) and extracts a masked key and the encrypteddata. The hashing function 300 calculates a message digest (MD)-5 hashof the encrypted data 310 to generate transformed data 312. Thede-masking function 332 calculates a XOR of the masked key 314 and thetransformed data 312 to generate a deterministic key 308. The decryptor334 decrypts the encrypted data 310 based on the deterministic key 308to produce data 306. The data 306 may include a data segment that issubsequently aggregated with other data segments to produce a dataobject as part of a retrieval sequence.

FIG. 18B is a flowchart illustrating an example of decoding a securepackage to produce data, which include similar steps to FIG. 17B. Themethod begins with step 336 where a processing module retrieves a securepackage. The retrieving includes at least one of receiving the securepackage and retrieving at least a decode threshold number of encodeddata slices of a set of encoded data slices from a dispersed storagenetwork (DSN) memory and dispersed storage error decoding the at leastthe decode threshold number of encoded data slices to produce the securepackage. The method continues at step 338 where the processing moduleextracts a masked key and encrypted data from the secure package. Themethod continues at step 322 of FIG. 17B where the processing modulegenerates transformed data from the encrypted data.

The method continues at step 342 where the processing module generates adeterministic key from the masked key and the transformed data. Themethod continues at step 344 where the processing module decrypts theencrypted data based on the deterministic key to produce data. Themethod continues at step 346 where the processing module transforms thedata into a validation key utilizing a hashing function. Atransformation includes performing a function on the data to produce thevalidation key, wherein the function includes one or more of a hashingfunction (e.g., message digest (MD)-5, secure hash algorithm (SHA)-1,SHA-256, SHA 512), a checksum function, a hash-based messageauthentication code (HMAC) (e.g., HMAC-MD-5), a mask generating function(MGF), and a compression function. The method continues at step 348where the processing module indicates that the data is valid when thevalidation key compares favorably (e.g., substantially the same) to thedeterministic key.

FIG. 19 is a schematic block diagram of an embodiment of a hardwareauthentication system. The authentication system may include a node 350to authenticate, a dispersed storage (DS) managing unit 18, and ahardware certificate authority (HCA) 352. The node may include one ormore of a computing core 26, a unit, a user device 12-14, a DS unit 36,a DS processing unit 16, a storage integrity processing unit 20, andanother DS managing unit 18.

The node 350 includes storage of a hardware certificate 354, a nodepublic key 356, and a node private key 358. The hardware certificate 354includes a device identifier (ID) 360, a serial number 362, a HCA publickey 364, a HCA private key 366. The device ID 360 provides a uniquevirtual identifier for hardware associated with node 350 (e.g., may notbe permanently assigned to the hardware). The serial number 362indicates a unique permanent value associated with the hardware (e.g.,determined at the time of manufacture). The HCA public key 364 and a HCAprivate key 366 are included in a public/private key pair associatedwith the HCA 352. The node public key 356 and a node private key 358 areincluded in a public/private key pair. For example, node 350 generatesthe node public key 356 and the node private key 358 as a public/privatekey pair associated with node 350.

The HCA 352 includes storage of a device list 368, the HCA public key364, and a HCA private key 370. The device list 368 includes one or moredevice IDs 360 and one or more paired device serial numbers 362associated with one or more nodes 350. The device list 368 may bereceived by the HCA 352 as one or more of a user input, apre-programming, an assembly-line output, a manufacturing computeroutput, a command, and a message. The HCA 352 sends the device list 368to the DS managing unit 18 from time to time or in response to a devicelist request from the DS managing unit 18. The HCA 352 sends the HCApublic key 364 to the DS managing unit 18 from time to time, in responseto a request, and/or upon a reboot of the DS managing unit 18.

The HCA 352 may produce a hardware certificate 354, wherein the hardwarecertificate 354 includes a device ID 360 and a paired serial number 362,the HCA public key 364, and a HCA signature 366. The HCA signature 366may be produced by the HCA 352 by calculating a hash of the hardwarecertificate 354 (e.g., without the HCA signature 366) and encrypting thehash utilizing the HCA private key 370. The HCA 352 sends the hardwarecertificate 354 to the node 350. For example, the HCA 352 sends hardwarecertificate 354 to the node 350 at a time of manufacture of the node350. As another example, the HCA 352 sends the hardware certificate 354to the node via a network when the node 350 is installed. The node 350receives the hardware certificate 354 from the HCA 352 and stores thehardware certificate in a local memory of the node 350. Alternatively,the node 350 may validate the hardware certificate 354 prior to storingthe hardware certificate 354 in the local memory. The validationincludes comparing a calculated hash of the hardware certificate 354 toa decrypted HCA signature utilizing the HCA public key 364 of thehardware certificate 354. The node 350 validates that the hardwarecertificate 354 when the comparison indicates that they aresubstantially the same.

The DS managing unit 18 includes storage of the device list 368 and theHCA public key 364. The DS managing unit 18 receives the device list 368from the HCA 352 and stores the device list 368 in local memory of theDS managing unit 18. Alternatively, the DS managing unit 18 may receivethe device list 368 as a user input or from any other unit of adispersed storage network (DSN) computing system. The DS managing unit18 receives the HCA public key 364 from the HCA 352 and stores the HCApublic key 364 in the local memory of the DS managing unit 18.Alternatively, the DS managing unit 18 receives the HCA public key 364from any node 350 in a registration sequence.

In an example of operation, the node 350 sends the hardware certificate354 to the DS managing unit 18 when the node 350 desires to authenticatethe hardware and join the DSN computing system. The DS managing unit 18validates the hardware certificate 354 (e.g., validates the HCAsignature 366) and compares the device ID 360 and/or serial number 362contained in the hardware certificate 354 to device IDs 360 in thelocally stored device list 368 when the hardware certificate 354 isvalid. The DS managing unit 18 validates the hardware when the DSmanaging unit 18 finds a matching device ID 360 and/or serial number 362of the hardware certificate 354 in the device list 368. Next, the DSmanaging unit 18 sends a challenge message 374 to the node 350 andreceives a challenge response 376 from the node 350. A challenge mayinclude a message that is encrypted utilizing the node public key 356.The node 350 decrypts the encrypted message of the challenge 374utilizing the node private key 358 to reproduce the message and sendsthe challenge response 376 to the DS managing unit 18, wherein thechallenge response 376 includes a message. The node 350 sends acertificate signing request 372 to the DS managing unit 18 and receivesa signed certificate 378 from the DS managing unit 18 enabling the nodeto communicate with other units and nodes of the DSN computing system.The method of operation of the node 350 and DS managing unit 18 arediscussed in greater detail with reference to FIGS. 20A and 20B.

FIG. 20A is a flowchart illustrating an example of acquiring a signedcertificate. The method begins with step 380 where a processing module(e.g., of a system node) receives a hardware certificate. The processingmodule may receive the hardware certificate from one or more of ahardware certificate authority (HCA), a dispersed storage (DS) managingunit, and any other element or unit of a dispersed storage network (DSN)computing system. For example, the processing module receives thehardware certificate from the HCA at a time of manufacture of thehardware when the processing module is functioning. The processingmodule saves the hardware certificate in a local memory and may validatethe hardware certificate by calculating a hash of the hardwarecertificate and comparing the hash to a decrypted signature where a HCAsignature is decrypted utilizing a HCA public key.

The method continues with step 382 where the processing moduledetermines to join a DSN system. Such a determination may be based onone or more of a predetermination, a boot up programming, aconfiguration file, a user input, a message, and a command. The methodcontinues at step 384 where the processing module sends the hardwarecertificate to a DS managing unit. Alternatively, the processing moduleencrypts the hardware certificate utilizing a node private keyassociated with the processing module prior to sending the hardwarecertificate to the DS managing unit.

The method continues at step 386 where the processing module receives achallenge message from the DS managing unit. A challenge may includeinstructions such as that the processing module is to decrypt a portionof the challenge message or to encrypt a response utilizing a privatekey of the node associated with the processing module. For example, theprocessing module receives a challenge message and decrypts a portion ofthe challenge message utilizing the node private key. The processingmodule forms a challenge response message utilizing the encryptedportion of the challenge message. As another example, the processingmodule encrypts a portion of the received challenge message utilizingthe node private key to form the challenge response message. The methodcontinues at step 388 where the processing module sends the challengeresponse message to the DS managing unit.

The method continues at step 390 where the processing module sends acertificate signing request (CSR) to the DS managing unit. The CSRincludes one or more of a device identifier (ID), a serial number of anode associated with the processing module, the node public key,registration information, and a signature. The method continues at step392 where the processing module receives a signed certificate from theDS managing unit. The signed certificate includes a signature from theDS managing unit. The processing module subsequently utilizes the signedcertificate to authenticate and communicate with other nodes of thesystem.

FIG. 20B is a flowchart illustrating an example of verifying acertificate signing request (CSR). The method begins with step 394 wherea processing module (e.g., a dispersed storage (DS) managing unit)receives a device list and a hardware certificate authority (HCA) publickey. The receiving includes at least one of receiving the device listand the HCA public key from an HCA, as a user input, as a command, andas a message. The method continues at step 396 where the processingmodule receives a hardware certificate from a node requesting toauthenticate hardware and join a dispersed storage network (DSN)computing system. For example, the processing module receives thehardware certificate from a DS unit during an initial installation.

The method continues at step 398 where the processing module determineswhether the hardware certificate is valid by validating a signature andvalidating a hardware device identifier (ID) and serial number. Theprocessing module validates the signature went a comparison of a hash ofthe hardware certificate to a decrypted HCA signature utilizing the HCApublic key indicates that they are substantially the same. Theprocessing module validates that the hardware device ID and/or serialnumber are listed in the device list to validate the hardware ID andserial number. The method branches to step 402 when the processingmodule determines that the hardware certificate is valid. The methodcontinues to step 400 when the processing module determines that thehardware certificate is not valid. The method continues at step 400where the processing module ignores the hardware certificate in themethod ends.

The method continues at step 402 where the processing module sends achallenge message to the node requesting hardware authentication. Achallenge message may include instructions to decrypt a portion of themessage that is encrypted utilizing the node public key or to encrypt aportion of a response message utilizing a private key of the node. Themethod continues at step 404 where the processing module receives achallenge response message from the node. The method continues at step406 where the processing module determines whether the challengeresponse message is valid by either validating that the responseincludes a decrypted version of a portion of the challenge message orthat the response may be decrypted utilizing the node public key toreveal a match to a portion of the challenge message. The methodbranches to step 410 when the processing module determines that thechallenge response message is valid. The method continues to step 408when the processing module determines that the challenge responsemessage is not valid. The method continues at step 408 where theprocessing module ignores the hardware certificate and the method ends.

The method continues at step 410 where the processing module receives acertificate signing request (CSR) from the node. The method continues atstep 412 where the processing module generates a signed certificate andsends the signed certificate to the node. For example, the processingmodule signs the certificate of the CSR by encrypting a portion of thesigned certificate utilizing a private key associated with theprocessing module (e.g., of the DS managing unit) and including a publickey associated with the processing module (e.g., of the DS managingunit) such that any node may subsequently validate the signedcertificate.

FIG. 21 is a schematic block diagram of an embodiment of a softwareupdate authentication system. The software may include one or more ofexecutable code, object code, source code, server code, client code,compiler code, debugger code, interpreter code, editor code, aninstruction set, graphical interface code, an operating system,information, low-level software, firmware code, diagnostic code,monitoring code, high-level code, an applet, a driver, an application,and a number table. A software update may include software that is aportion of total software of a dispersed storage network (DSN) computingsystem and/or contain newer software that may be utilized to update afielded computing device of the DSN computing system.

A software update authentication system includes a node 350, a dispersedstorage (DS) managing unit 18, and a software update authority (SUA)414. The node may include any element, unit, computing core 26 of theDSN system such as any one or more of a user device 12-14, a DSprocessing unit 16, a DS managing unit 18, a storage integrityprocessing unit 20, and a DS unit 36. The node 350 includes storage ofauthenticated software 416 and an update public key 418. The updatepublic key 418 is associated with a public/private key pair of the SUA414. The DS managing unit 18 includes storage of a signed softwareupdate 420 and the update public key 418.

The SUA 414 includes a processing module and memory and may be locatedat a geographically different site than the other system units. Thesoftware update authority 414 includes storage of a software update 422,an update private key 424, and the update public key 418. The SUA 414sends the update public key 418 to the DS managing unit 18 from time totime, in response to a request, and/or upon a reboot of the DS managingunit 18. The SUA 414 sends the update public key 418 to the node 350from time to time, in response to a request, and/or upon a reboot of thenode 350.

The software update authority 414 receives the software update 422 fromany one of a user input, a manufacturing system output, a third-partyvendor, an internet source, a file sharing source, from slices stored ina DSN memory, a programming computer output, a physical media device,and any other source of software. The software update authority 414saves the software update 422 in a local memory. The software updateauthority 414 produces a signature to produce the signed software update420. For example, the software update authority 414 encrypts acalculated hash of the software update to produce the signatureutilizing the update private key 424. As another example, the softwareupdate authority 414 encrypts a calculated hash of a software updatemessage to produce the signature utilizing the update private key 424.The software update authority 414 appends one or more of the signatureand the update public key 418 to the software update 422 to produce thesigned software update 420. The software update authority 414 sends thesigned software update 420 to the DS managing unit 18 for furtherdistribution to one or more nodes 350 of the DSN computing system.

The DS managing unit 18 receives the signed software update 420 from thesoftware update authority 414 and stores the signed software 420 updatea local memory of the DS managing unit 18 to facilitate distribution toone or more nodes 350 of the DSN computing system. In addition, the DSmanaging unit 18 may verify the signed software update 420 prior tosaving the signed software update 420 in the local memory. The DSmanaging unit 18 verifies the signed software update 420 by comparing ahash of a portion of the software update 420 to a decrypted signatureutilizing the update public key 418. The DS managing unit 18 determinesthat the signed software update 420 is favorably verified when thecomparison indicates that the hash and the decrypted signature aresubstantially the same. The DS managing unit 18 sends the locally storedsigned software update 420 to one or more system nodes based on one ormore of a time period that has elapsed since a previous software updatecycle, in response to a request from any node, and in response to a pushcommand from the software update authority 414.

The node 350 receives the signed software update 420 from the DSmanaging unit 18 and verifies the signed software update 420 bycomparing the hash of the portion of the software update to a decryptedsignature utilizing the update public key 418. The node 350 determinesthat the signed software update 420 is verified when the comparisonindicates that the hash and the decrypted signature are substantiallythe same. The node 350 produces the authenticated software 416 from thesigned software update 420 when the node 350 determines that the signedsoftware update 320 is verified. The node saves the authenticatedsoftware 416 in the local memory of the node 350. In addition, the nodeutilizes the locally stored authenticated software 416 to performfunctions of the node 350 by executing at least a portion of theauthenticated software 416 from time to time. The method of operation ofthe software update authority 414 and the node is discussed in greaterdetail with reference to FIGS. 22A and 22B.

FIG. 22A is a flowchart illustrating an example of generating a signedsoftware update. The method begins with step 426 where a processingmodule (e.g., of a software update authority) sends an update public keyto one or more nodes and/or dispersed storage DS managing unit(s) of adispersed storage network (DSN) computing system. Such an update publickey is part of a public/private key pair associated with the softwareupdate authority and is utilized throughout the DSN computing system tovalidate communications to and from the software update authority.

The method continues at step 428 where the processing module receives asoftware update from any one of a user input, a manufacturing systemoutput, a third-party vendor, an internet source, a file sharing source,from slices stored in a DSN memory, a programming computer output, aphysical media device, and any other source of software. The processingmodule saves the software update in local memory. The method continuesat step 430 where the processing module determines a hash of thesoftware update. For example, the processing module calculates the hashof the software update utilizing a message digest (MD)-5 hash algorithm.The method continues at step 432 where the processing module encryptsthe hash of the software update to produce a signature utilizing anupdate private key of the public/private key pair associated with thesoftware update authority.

The method continues with step 434 where the processing module appendsthe signature to the software update to produce a signed softwareupdate. The method continues at step 436 where the processing modulesends the signed software update to the DS managing unit and/or one ormore other system nodes. Additionally, the processing module saves thesigned software update in local memory.

FIG. 22B is a flowchart illustrating an example of authenticating asigned software update. The method begins with step 438 where aprocessing module (e.g., of a system node) receives an update public keyfrom one of a software update authority and a dispersed storage (DS)managing unit. The processing module may receive the update public keyfrom time to time, in response to a query, substantially alone in amessage, included with a signed certificate message, and included with asigned software update. For example, the processing module receives theupdate public key from the software update authority in message at thetime of manufacture.

The method continues at step 440 where the processing module receives asigned software update from the DS managing unit from time to time, inresponse to a query, or as a push message. Alternatively, the processingmodule receives the signed software update from one of the softwareupdate authority, the user device, the DS processing unit, the DS unit,or a publisher.

The method continues at step 442 where the processing module determinesa hash of the signed software update. For example, the processing modulecalculates the hash utilizing a message digest (MD)-5 hash algorithm.The method continues at step 444 where the processing module decrypts asignature of the signed software update utilizing the update public keyto produce a decrypted signature. The method continues at step 446 wherethe processing module determines whether the hash of the signed softwareupdate compares favorably to the decrypted signature. The processingmodule determines that the hash compares favorably to the decryptedsignature when the hash and the decrypted signature is substantially thesame. The method branches to step 450 when the processing moduledetermines that the hash compares favorably to the decrypted signature.The method continues to step 448 when the processing module determinesthat the hash compares unfavorably to the decrypted signature. Themethod continues with step 448 where the processing module ignores thesoftware update and the method ends. The method continues at step 450where the processing module saves the software update as authenticatedsoftware when the processing module determines that the hash comparesfavorably to the decrypted signature. In addition, the processing modulemay utilize at least a portion of the authenticated software as theprocessing module performs functions associated with the processingmodule.

Alternatively, or in addition to, the processing module receives apublic key from a trusted node (e.g., a DS unit) of the DSN computingsystem. The processing module receives a signed software update from thetrusted node and validates that the signed software update was sent fromthe trusted node by validating the communications message. Theprocessing module validates the signed software update and saves thesoftware update as authenticated software when the processing moduledetermines that the signed software update is valid and that themedications message from the trusted node is valid.

FIG. 23 is a schematic block diagram of an embodiment of a cooperativestorage system. A system includes one or more user devices 1-2, or moredispersed storage (DS) processing units 1-3, one or more dispersedstorage network (DSN) memories 1-2, and a DS managing unit 18. A userdevice 1-2 stores data as a plurality of portions in at least one DSNmemory and retrieve the data portions from the at least one DSN memoryutilizing one or more DS processing units 1-3, wherein the DS processingunits 1-3 are associated with the plurality of portions of the data. TheDS managing unit 18 includes a portion affiliation table 452. Theportion affiliation table 452 includes associations between one or moreentries of a DS processing unit identifiers field (ID) 454 and acorresponding one or more entries of a portion identifier (ID) field456. For example, a DS processing unit ID field 454 entry of 3 isassociated with portion ID field 456 entries of 2 and 3. As such, DSprocessing unit 3 is assigned to store and retrieve a second and a thirdportion of data as slices 11.

In a storage example of operation, user device 1 determines affiliationinformation including affiliations between DS processing unit IDs andportion IDs. Such a determination may be based on one or more of astorage algorithm user device 1, a predetermination, a vault lookup, andreceiving affiliation information 460 from the DS managing unit 18. Theuser device 1 partitions a data object for storage into six portions inaccordance with the affiliation information 460. The user device 1 sendsportions 1, 5, and 6 to DS processing unit 1 for storage in accordancewith the affiliation information 460. The user device 1 sends theportion 4 to DS processing unit 2 for storage in accordance with theaffiliation information 460. The user device 1 sends portions 2 and 3 toDS processing unit 3 for storage in accordance with the affiliationinformation 460.

The DS processing units 1-4 receives the portions 1-6 and save theportions by at least one of storing the portions locally and dispersedstorage error encoding each portion to produce slices 11 and sending theslices 11 to one or more DSN memories for storage therein. For example,DS processing unit 1 dispersed storage error encodes portion 1 toproduce portion 1 slices. The method to store data is discussed ingreater detail with reference to FIG. 24A.

In a retrieval example of operation, user device 2 determinesaffiliation information indicating which DS processing unit IDs toretrieve which portions of desired data. Such a determination may bebased on one or more of a storage algorithm, a predetermination, a vaultlookup, a message from user device 1, and receiving the affiliationinformation 460 from the DS managing unit. The user device 2 retrievesportions of the data from the DS processing units in accordance with theaffiliation information 460. For example, user device 2 retrievesportions 1, 5, and 6 from DS processing unit 1, portion 4 from DSprocessing unit 2, and portions 2 and 3 from DS processing unit 3. Theuser device 2 aggregates the portions in sequential order to reproducethe data. The method to retrieve data is discussed in greater detailwith reference to FIG. 24B.

In an alternative embodiment, a DS processing of the DS processing units1-3 is implemented in the user devices 1-2 thus eliminating the need forDS processing units. As such, the user devices 1-2 create portions ofthe data, create slices of the portions, store the slices in the DSNmemory, and update the portion affiliation table 452 in the DS managingunit 18. A retrieving user device determines the affiliation information460 by querying the DS managing unit, re-creates the portions of thedata by retrieving slices from at least one DSN memory, and aggregatesthe portions to reproduce the data.

FIG. 24A is a flowchart illustrating an example of storing data inaccordance with the invention. The method begins with step 462 where aprocessing module (e.g., of user device) partitions data for storageinto two or more data portions. The partitioning may be done bypartitioning the data in accordance with one of a predetermined approachor an approach received via a command. For example, the processingmodule partitions the data into 100 portions in accordance with apredetermined approach from a user device configuration file.

The method continues at step 464 where the processing module determinesportion affiliation information of the data portions. For example, theprocessing module may assign dispersed storage (DS) units in accordancewith at least one of a predetermination, a command, a message, a lookup,and received portion affiliation information in response to a query of aDS managing unit. A query includes sending a portion affiliationinformation assignment request to the DS managing unit. The processingmodule receives the portion affiliation information from the DS managingunit including affiliations of DS processing units and portionidentifiers of the data.

The method continues at step 466 where the processing module sends thedata portions to affiliated DS processing units for storage inaccordance with the portion affiliation information. The DS processingunit receives the data portion. The DS processing unit determines acooperative storage method based on one or more of a lookup, apredetermination, a query, a command, and a message. For example, the DSprocessing unit determines the cooperative storage method based on aquery to the DS managing unit. The cooperative storage method mayinclude guidance on how to process the data portion prior to storing thedata portion. For example, the guidance may indicate to store the dataportion as a data portion in local memory. As another example, theguidance may indicate to create data slices directly from the dataportion and store the data slices in one or more dispersed storagenetwork (DSN) memories. As yet another example, the guidance mayindicate to create two or more data segments from the data portion andcreate data slices from each data segment to store in at least one DSNmemory. As a still further example, the guidance may indicate to storepart of the data portion in local memory and the other part of the dataportion as data slices in at least one DSN memory.

The DS processing unit stores the data portion in accordance with theguidance. Such creating of data slices includes dispersed storage errorencoding portion data (e.g., at least a part of a data portion). Thedispersed storage error encoding may utilize different error codingdispersal storage function parameters from DS processing unit two DSprocessing unit such that data slices stored in at least one DSN memoryare created differently from DS processing unit to DS processing unitfor different data portions of the data.

The method continues at step 468 where the processing module facilitatesstorage of the portion affiliation information in a DS managing unit.For example, the processing module sends the portion affiliationinformation to the DS managing unit for storage therein. As anotherexample, the processing module sends a confirmation message to the DSmanaging unit that the portion affiliation information received inresponse to a DS managing unit query was utilized in the storagesequence. As such, the processing module confirms that the DS units anddata portions chosen by the DS managing unit were utilized in thestorage sequence.

FIG. 24B is a flowchart illustrating an example of retrieving data. Themethod begins with step 470 where a processing module (e.g., a userdevice) retrieves portion affiliation information from a dispersedstorage (DS) managing unit. The receiving includes the module sending aportion affiliation information request message to the DS managing unitto retrieve the portion affiliation information. The processing modulereceives the portion affiliation information from the DS managing unit.

The method continues at step 472 where the processing module determinesthe DS processing units affiliated with the data portions based on theportion affiliation information. The method continues at step 474 wherethe processing module sends the DS processing units data portionretrieval requests in accordance with the portion affiliationinformation. The data portion retrieval request includes a portion IDand a retrieval request code. The DS processing unit may retrieve a dataportion by at least one of directly from local memory, from local memoryand from at least one dispersed storage network (DSN) memory, and fromat least one DSN memory. The DS processing units may utilize a differenterror coding dispersal storage function parameters in reconstructing thedata portions from retrieved data slices. The method continues at step476 where the processing module receives data portions from the DSprocessing units. The method continues at step 478 where the processingmodule aggregates the data portions to produce the data in accordancewith the portion affiliation information.

FIG. 25 is a schematic block diagram of an embodiment of a mediaredistribution system. The system includes a media server 480 and aplurality of user devices 1-3. The user devices 1-3 include one or moreof a dispersed storage (DS) processing 34, a dispersed storage network(DSN) memory 22, a DS unit 36, a user interface (e.g., a display screenand speaker to view and listen to a media broadcast), at least onewireless device, and at least one wireline interface. Such user devices1-3 may be affiliated as neighboring devices to each other (e.g.,affiliated to same group, affiliated by distance). The media server 480provides a media broadcast 482 to the plurality of user devices 1-3. Themedia broadcast 482 may include one or more of audio streaming, videostreaming, multimedia streaming, music streaming, video files, audiofiles, and multimedia files. The media broadcast 482 may be communicatedin one or more of a format native to an industry standard (e.g., MPEG2or video, MP4 for music, etc.), as a dispersed error encoded file, andas a plurality of sets of encoded data slices.

The media server 480 may be operably coupled to the plurality of userdevices 1-3 by way of a wireline and/or a wireless network. Theplurality of user devices 1-3 may be operably coupled to each other byway of the wireline and/or the wireless network. As such, any userdevice of the plurality of user devices 103 may not be able tocommunicate directly with the media server 480 when wireless signalingconditions prohibit a connection to facilitate communications when thewireless network is utilized for connectivity. A pair of user devices ofthe plurality of user devices 1-3 may be able to communicate with eachother utilizing a first wireless network and at least one user device ofthe pair of user devices may be able to communicate to a third userdevice utilizing a second wireless network. For example, user devices 1and 2 are able to communicate directly to the media server 480 and userdevice 3 is able to communicate to user devices 1 and 2, but notdirectly to the media server 480.

In a first mode of operation, a first user device receives the mediabroadcast 482 directly from the media server 480, obtains data slicesfrom the media broadcast 482, and stores the data slices in a local DSNmemory associated with the first user device. The obtaining includes atleast one of dispersed storage error encoding the media broadcast 482 toproduce the data slices and extracting the data slices from the mediabroadcast 482. The first user device may subsequently retrieve the dataslices of the media broadcast from the local DSN memory for furtherprocessing (e.g., listening and watching via a user interface associatedwith the first user device). The first user device may send at leastsome of the data slices 484 of the media broadcast to a second userdevice when the second user device has a desire for the media broadcast.

In a second mode of operation, a second user device receives at leastsome data slices 484 of the media broadcast from the first user deviceand saves the at least some data slices in a local DSN memory associatedwith the second user device. The second user device may receive the sameor different data slices 486 of the same media broadcast from anotheruser device other than the first user device. The second user devicereceives at least a decode threshold number of slices corresponding toeach data segment of a plurality of data segments of the media broadcastfrom one or more other user devices to enable dispersed storage errordecoding of each data segment of the media broadcast. The second userdevice may retrieve the data slices of the media broadcast from thelocal DSN memory associated with the second user device for furtherprocessing (e.g., listening and watching via a user interface associatedwith the second user device). The second user device may send at leastsome of the data slices of the media broadcast to a third user device.

In an example of operation, the media server 480 sends the mediabroadcast 482 to user device 1 and as a duplicate media broadcast touser device 2. The sending includes at least one of transmitting themedia broadcast 482 in a video stream format and transmitting the mediabroadcast 482 in a data slice format. User device 1 receives the mediabroadcast 482 from the media server 480. User device 1 createssequential data segments of the media broadcast and produces data slicesof each data segment in accordance with an error coding dispersalstorage function when the media broadcast is received in a video streamformat. User device 1 stores the data slices in a local DSN memoryassociated with user device 1. For example, user device 1 stores thedata slices in one or more of the main memory 54, flash memory via theflash interface module 72, a hard drive via the hard drive interfacemodule 74, and local DSN memory via DSN interface module 76.Alternatively, user device 1 sends at least some of the data slices 484to one or more other user devices for storage therein. User device 1subsequently retrieves the data slices from the local DSN memory,dispersed storage error decodes the data slices to reproduce the mediabroadcast 482, and outputs the media broadcast 482 to a user interfaceassociated with user device 1.

In another example of operation, user device 2 receives the mediabroadcast 482 from the media server 480, obtains and stores data slicesof the media broadcast 482, and subsequently retrieves the data slicesto re-create the media broadcast and provide the media broadcast 482 toa user interface associated with user device 2. User device 2 mayutilize substantially a same error coding dispersal storage functionparameters when creating the data slices of the media broadcast 482 suchthat another user device receiving forwarded data slices 484 & 486 fromuser devices 1 and 2 may more effectively re-create the media broadcast.For instance, user devices 1 and 2 forward data slices of every pillarto another user device as slices 484 and slices 486. As anotherinstance, user devices 1 and 2 coordinate the sending of data slices ofthe pillars such that data slices of overlapping pillars is at leastpartially minimized. As such, not all of the pillars are forwarded fromboth of user devices 1 and 2. User devices 1 and 2 may coordinate thesending of the pillars by communicating coordination information betweeneach other or by receiving coordination information from the mediaserver 480.

In yet another example of operation, user device 3 determines thatcommunications directly with the media server 480 is not possible. Userdevice 3 determines that communications with user device 1 and 2 ispossible. User device 3 determines that user device 1 and 2 arereceiving a desired media broadcast 482 from the media server 480. Userdevice 3 sends a media broadcast slice request to user devices 1 and 2.User devices 1 and 2 send at least some data slices 484 & 486 of themedia broadcast 482 to user device 3. User device 3 receives at leastsome data slices 484 from user device 1 and at least some data slices486 from user device 2. For instance, user device 3 receives data slices484 of pillars 1 through k from user device 1 (e.g., a decode thresholdnumber for each data segment) and receives data slices 486 of pillarsk+1 through n from user device 2. The method of operation is discussedin greater detail with reference to FIG. 26.

FIG. 26 is a flowchart illustrating an example of redistributing mediain accordance with the invention. The method begins with step 488 wherea processing module (e.g., of a user device) determines to retrieve adispersed error encoded file from a dispersed storage network (DSN),wherein the dispersed error encoded file is stored as a plurality ofsets of encoded data slices and wherein a data segment of the file isencoded into a set of encoded data slices of the plurality of sets ofencoded data slices. The DSN may be affiliated with one or more of amedia server, a plurality of user devices affiliated with a present userdevice, a standalone DSN, and a memory of another user device. Thedetermination to retrieve the dispersed error encoded file includes oneor more of receiving a request, interpreting a command, receiving a userinput, and determining a user preference.

The method continues at step 490 where the processing module determineswhether a neighboring device has a desire to retrieve the dispersederror encoded file. The determining includes one or more of querying theneighboring device, receiving a dispersed error encoded file retrievalrequest from the neighboring device, accessing a neighboring devicepreference indicator (e.g., media content that is likely to be desired),accessing a look up table, and determining that the neighboring deviceis affiliated with a user group of the device. The method branches tostep 496 when the processing module determines that the neighboringdevice does not have the desire to retrieve the dispersed error encodedfile. The method continues to step 492 when the processing moduledetermines that the neighboring device has the desire to retrieve thedispersed error encoded file.

The method continues at step 492 where the processing module coordinatesretrieving of the dispersed error encoded file such that, collectively,the device and the neighboring device receive at least a decodethreshold number of encoded data slices of each data segment of aplurality of data segments of the dispersed error encoded file. Suchreceiving includes receiving at least a decode threshold number ofencoded data slices of a first set of encoded data slices and at leastthe decode threshold number of encoded data slices of a second set ofencoded data slices.

The coordinating includes at least one of the device retrieving a firstportion of each of the at least the decode threshold number of encodeddata slices of the first and second sets of encoded data slices and theneighboring device retrieving a second portion of each of the at leastthe decode threshold number of encoded data slices of the first andsecond sets of encoded data slices; the device retrieving the at leastthe decode threshold number of encoded data slices of the first set ofencoded data slices and the neighboring device retrieving the at leastthe decode threshold number of encoded data slices of the second set ofencoded data slices; and the device retrieving the at least the decodethreshold number of encoded data slices of the first set and second setof encoded data slices and the device forwarding the at least the decodethreshold number of encoded data slices of the first set and second setof encoded data slices to the neighboring device.

The method continues at step 494 where the processing module stores theat least the decode threshold number of encoded data slices of each datasegment of the plurality of data segments of the dispersed error encodedfile. The storing includes storing the at least the decode thresholdnumber of encoded data slices of the first set and second set of encodeddata slices. The storing includes at least one of storing the at leastthe decode threshold number of encoded data slices of the first set andsecond set of encoded data slices as received and transcoding the atleast the decode threshold number of encoded data slices of the firstset and second set of encoded data slices from a first set of dispersedstorage error coding parameters to a second set of dispersed storageerror coding parameters to produce transcoded sets of encoded dataslices and storing the transcoded sets of encoded data slices.

The method continues at step 496 where the processing module retrievesat least the decode threshold number of encoded data slices of each datasegment of the plurality of data segments of the dispersed error encodedfile when the processing module determines that the neighboring devicedoes not have the desire to retrieve the dispersed error encoded file.Such retrieving includes receiving at least a decode threshold number ofencoded data slices of the first set of encoded data slices and at leastthe decode threshold number of encoded data slices of the second set ofencoded data slices.

The method continues at step 498 where the processing module stores theat least the decode threshold number of encoded data slices of each datasegment of the plurality of data segments of the dispersed error encodedfile. The storing includes storing the at least the decode thresholdnumber of encoded data slices of the first set and second set of encodeddata slices. The storing includes at least one of storing the at leastthe decode threshold number of encoded data slices of the first set andsecond set of encoded data slices as received and transcoding the atleast the decode threshold number of encoded data slices of the firstset and second set of encoded data slices from the first set ofdispersed storage error coding parameters to the second set of dispersedstorage error coding parameters to produce transcoded sets of encodeddata slices and storing the transcoded sets of encoded data slices.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “operably coupled to”, “coupled to”, and/or “coupling” includesdirect coupling between items and/or indirect coupling between items viaan intervening item (e.g., an item includes, but is not limited to, acomponent, an element, a circuit, and/or a module) where, for indirectcoupling, the intervening item does not modify the information of asignal but may adjust its current level, voltage level, and/or powerlevel. As may further be used herein, inferred coupling (i.e., where oneelement is coupled to another element by inference) includes direct andindirect coupling between two items in the same manner as “coupled to”.As may even further be used herein, the term “operable to” or “operablycoupled to” indicates that an item includes one or more of powerconnections, input(s), output(s), etc., to perform, when activated, oneor more its corresponding functions and may further include inferredcoupling to one or more other items. As may still further be usedherein, the term “associated with”, includes direct and/or indirectcoupling of separate items and/or one item being embedded within anotheritem. As may be used herein, the term “compares favorably”, indicatesthat a comparison between two or more items, signals, etc., provides adesired relationship. For example, when the desired relationship is thatsignal 1 has a greater magnitude than signal 2, a favorable comparisonmay be achieved when the magnitude of signal 1 is greater than that ofsignal 2 or when the magnitude of signal 2 is less than that of signal1.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described, at least in part, in terms ofone or more embodiments. An embodiment of the present invention is usedherein to illustrate the present invention, an aspect thereof, a featurethereof, a concept thereof, and/or an example thereof. A physicalembodiment of an apparatus, an article of manufacture, a machine, and/orof a process that embodies the present invention may include one or moreof the aspects, features, concepts, examples, etc. described withreference to one or more of the embodiments discussed herein.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

1. A method comprises: sending list digest requests to a set of dispersed storage (DS) units, wherein a list digest request of the list digest requests is requesting a representation of a slice name information list regarding encoded data slices stored by a DS unit of the set of DS units; receiving list digest responses from at least some of the set of DS units; determining whether an inconsistency exists between first and second list digest responses of the list digest responses; and when the inconsistency exists between first and second list digest responses of the list digest responses: requesting at least a portion of each of the slice name information lists from first and second DS units of the set of DS units, wherein the first DS unit provided the first list digest response and the second DS unit provided the second list digest response; and identifying a slice name information error associated with the inconsistency based on the at least a portion of each of the slices name information lists of the first and second DS units.
 2. The method of claim 1, wherein the representation of the slice name information list comprises at least one of: a hash value resulting from a hash function performed on entries of the slice name information list; a compression value resulting from a compression function performed on entries of the slice name information list; a checksum value resulting from a checksum function performed on the entries of the slice name information list; a hash-based message authentication code (HMAC) value resulting from an HMAC function performed on the entries of the slice name information list; and a mask generating function (MGF) value resulting from an MGF performed on the entries of the slice name information list.
 3. The method of claim 1, wherein the determining whether the inconsistency exists between the first and the second list digest responses comprises at least one of: a first hash value of the first list digest response is not substantially equal to a second hash value of the second list digest response; a first checksum value of the first list digest response is not substantially equal to a second checksum value of the second list digest response; a first HMAC value of the first list digest response is not substantially equal to a second HMAC value of the second list digest response; and a first MGF value of the first list digest response is not substantially equal to a second MGF value of the second list digest response.
 4. The method of claim 1, wherein the identifying the slice name information error comprises: establishing the at least a portion of the slice name information list from the first DS unit as a current slice name information list; and identifying an entry of the at least a portion of the slice name information list from the second DS unit that differs from a corresponding entry of the at least a portion of the slice name information list from the first DS unit to identify the slice name information error.
 5. The method of claim 4, wherein the establishing the at least a portion of the slice name information list from the first DS unit as the current slice name information list comprises: determining that the at least a portion of the slice name information list from the first DS unit substantially matches at least a portion of the slice name information list from a third DS unit of the set of DS units.
 6. The method of claim 1 further comprises: the slice name information list including a plurality of entries for a range of slice names, wherein an entry of the plurality of entries includes: a slice name of a corresponding one of the encoded data slices; a slice revision count indicating a number of revisions of the slice name; and for a revision of the revisions of the slice names: a revision number; and a slice length indicator.
 7. The method of claim 1 further comprises: adding the slice name information error to a rebuild list.
 8. The method of claim 1, wherein the slice name information error comprises at least one of: a missing encoded data slice error; a non-deleted encoded data slice error; and a revision error.
 9. A computer comprises: an interface; a memory; and a processing module operable to: send, via the interface, list digest requests to a set of dispersed storage (DS) units, wherein a list digest request of the list digest requests is requesting a representation of a slice name information list regarding encoded data slices stored by a DS unit of the set of DS units; receive, via the interface, list digest responses from at least some of the set of DS units; determine whether an inconsistency exists between first and second list digest responses of the list digest responses; and when the inconsistency exists between first and second list digest responses of the list digest responses: request, via the interface, at least a portion of each of the slice name information lists from first and second DS units of the set of DS units, wherein the first DS unit provided the first list digest response and the second DS unit provided the second list digest response; and identify a slice name information error associated with the inconsistency based on the at least a portion of each of the slices name information lists of the first and second DS units.
 10. The computer of claim 9, wherein the representation of the slice name information list comprises at least one of: a hash value resulting from a hash function performed on entries of the slice name information list; a compression value resulting from a compression function performed on entries of the slice name information list; a checksum value resulting from a checksum function performed on the entries of the slice name information list; a hash-based message authentication code (HMAC) value resulting from an HMAC function performed on the entries of the slice name information list; and a mask generating function (MGF) value resulting from an MGF performed on the entries of the slice name information list.
 11. The computer of claim 9, wherein the processing module functions to determine whether the inconsistency exists between the first and the second list digest responses by at least one of: a first hash value of the first list digest response is not substantially equal to a second hash value of the second list digest response; a first checksum value of the first list digest response is not substantially equal to a second checksum value of the second list digest response; a first HMAC value of the first list digest response is not substantially equal to a second HMAC value of the second list digest response; and a first MGF value of the first list digest response is not substantially equal to a second MGF value of the second list digest response.
 12. The computer of claim 9, wherein the processing module functions to identify the slice name information error by: establishing the at least a portion of the slice name information list from the first DS unit as a current slice name information list; and identifying an entry of the at least a portion of the slice name information list from the second DS unit that differs from a corresponding entry of the at least a portion of the slice name information list from the first DS unit to identify the slice name information error.
 13. The computer of claim 12, wherein the processing module functions to establish the at least a portion of the slice name information list from the first DS unit as the current slice name information list by: determining that the at least a portion of the slice name information list from the first DS unit substantially matches at least a portion of the slice name information list from a third DS unit of the set of DS units.
 14. The computer of claim 9 further comprises: the slice name information list including a plurality of entries for a range of slice names, wherein an entry of the plurality of entries includes: a slice name of a corresponding one of the encoded data slices; a slice revision count indicating a number of revisions of the slice name; and for a revision of the revisions of the slice names: a revision number; and a slice length indicator.
 15. The computer of claim 9, wherein the processing module further functions to: add the slice name information error to a rebuild list.
 16. The computer of claim 9, wherein the slice name information error comprises at least one of: a missing encoded data slice error; a non-deleted encoded data slice error; and a revision error. 